৪৯তম বিসিএস ⎯ প্রাণিবিদ্যা [৫৯১]

The famous novel, The Bluest Eye, is written by - American author.

• The Bluest Eye:
- এটি Toni Morrison রচিত।
- এটি একটি novel.
- এটি ১৯৭০ সালে প্রকাশিত হয়।

• Toni Morrison ছিলেন একজন আমেরিকান Novelist, essayist এবং Editor.
- তাছাড়া তিনি Princeton University এর প্রফেসর ছিলেন।

তাঁর উল্লেখযোগ্য সাহিত্যকর্ম গুলো -
- Beloved,
- Song of Solomon,
- The Bluest Eye.

Source: Britannica.

বাংলাদেশের তত্ত্বাবধায়ক সরকার:
- বাংলাদেশের তত্ত্বাবধায়ক সরকার বাংলাদেশের একপ্রকারের শাসন ব্যবস্থা, যার অধীনে দুইটি নির্বাচিত সরকারের মধ্যবর্তী সময়কালে সাময়িকভাবে অনির্বাচিত ব্যক্তিবর্গ কোন দেশের শাসনভার গ্রহণ করে থাকে।
- বিএনপি সরকারের পদত্যাগের পর ১৯৯৬ সালে ত্রয়োদশ সংশোধনের মাধ্যমে সংবিধানে যোগ হয় তত্ত্বাবধায়ক সরকার পদ্ধতি।
- এই সংশোধনীর মাধ্যমে ১৯৯৬ সালে সাংবিধানিকভাবে তত্ত্বাবধায়ক সরকার ব্যবস্থা চালু হয়।
- বিচারপতি মুহাম্মদ হাবিবুর রহমান ছিলেন সেই তত্ত্বাবধায়ক সরকারের প্রধান উপদেষ্টা।
- উপদেষ্টা পরিষদের বাকিরা হলেন: ব্যারিস্টার সৈয়দ ইশতিয়াক আহমেদ, ড. মুহাম্মদ ইউনূস, অর্থনীতিবিদ ড. ওয়াহিদউদ্দিন মাহমুদ, অধ্যাপক মো. শামসুল হক, অধ্যাপক জামিলুর রেজা চৌধুরী, শেগুফতা বখত চৌধুরী, এ জেড এম নাছিরুদ্দিন, সৈয়দ মঞ্জুর এলাহী, অধ্যাপক নাজমা চৌধুরী ও মেজর জেনারেল (অব.) আব্দুর রহমান খান।
- এই তত্ত্বাবধায়ক সরকার মোট ৮৬ দিন ক্ষমতায় ছিল। এই সরকার ১৯৯৬ সালের ১২ জুন জাতীয় সংসদের নির্বাচনের তারিখ ঘোষণা করেন।
- অবশেষে বিপুল উৎসাহ ও উদ্দীপনা মধ্য দিয়ে ১৯৯৬ সালের ১২ জুন তত্ত্বাবধায়ক সরকারের অধীন প্রথম সপ্তম জাতীয় সংসদ নির্বাচন অনুষ্ঠিত হয়।

উল্লেখ্য,
- ১৯৯০ সালে সেনাশাসক হুসেইন মুহম্মদ এরশাদের পতনের পর জাতীয় নির্বাচন আয়োজন পর্যন্ত দায়িত্ব পালনের জন্য গঠন করা হয়েছিল নির্দলীয় প্রথম অন্তর্বর্তীকালীন সরকার।
- প্রধান বিচারপতি শাহাবুদ্দিন আহমেদের নেতৃত্বে ঐ সরকার গঠিত হয়েছিল।

এছাড়াও,
- ৩০ জুন, ২০১১ সালে পঞ্চদশ সংশোধনীর মাধ্যমে বাংলাদেশের সংবিধান থেকে 'তত্ত্বাবধায়ক সরকার ব্যবস্থা' বাতিল করা হয়।

উৎস: ইতিহাস ২য় পত্র, এইচএসসি প্রোগ্রাম, বাংলাদেশ উন্মুক্ত বিশ্ববিদ্যালয়।

তিস্তা মহাপরিকল্পনা:
- তিস্তা মহাপরিকল্পনা বাস্তবায়নে সহায়তা করবে চীন।

⇒ তিস্তা প্রকল্পের প্রথম পর্যায় বাস্তবায়নে ব্যয় হবে ৭৫ কোটি ডলার। এর মধ্যে চীন থেকে ঋণ চাওয়া হয়েছে ৫৫ কোটি ডলার। বাকিটা করা হবে সরকারি অর্থায়নে।
- চীনের রাস্ট্রদূত জানান, তিস্তা প্রকল্পের বিষয়টিতে অর্থ মন্ত্রণালয়ের অর্থনৈতিক সম্পর্ক বিভাগের (ইআরডি) সঙ্গে তারা কাজ করছেন।
- চীনের বিশেষজ্ঞ দল তিস্তা প্রকল্পের সম্ভাবনা যাচাই শেষে অক্টোবর, ২০২৫-এর মধ্যে তিস্তা মহাপরিকল্পনার ডিজাইন চূড়ান্ত হবে।
- ২০২৬ সালে এ প্রকল্পের কাজ শুরু করে ২০২৯ সালে শেষ করার লক্ষ্যমাত্রা নির্ধারণ করা হয়েছে।
- মহাপরিকল্পনায় তিস্তা নদীর ডান-বাম উভয় তীর ঘেঁষে ২২০ কিলোমিটার উঁচু গাইড বাঁধ, রিভার ড্রাইভ, হোটেল-মোটেল-রেস্তোরাঁ, পর্যটন কেন্দ্র, ১৫০ মেগাওয়াট সৌর বিদ্যুতকেন্দ্র, শিল্প-কারখানা, ইপিজেড, ইকোনমিক জোন, কয়েক লাখ হেক্টর কৃষি জমি উদ্ধার, বনায়ন ইত্যাদি রয়েছে।
- এ প্রকল্প বাস্তবায়ন হলে তিস্তা পাড় হয়ে উঠবে পূর্ব চীনের জিয়াংসু প্রদেশের সুকিয়ান সিটির মতো সুন্দর নগরী।

উৎস: i) প্রথম আলো।
ii) দৈনিক ইনকিলাব।

ড্রাগন ফল উৎপাদন:
- কৃষি সম্প্রসারণ অধিদপ্তরের তথ্য অনুযায়ী, ড্রাগন উৎপাদনের শীর্ষে আছে ঝিনাইদহ জেলা।
- ২০২৪-২৫ অর্থবছরে উৎপাদন হয় ৩২ হাজার ৭৬৮ মেট্রিক টন ড্রাগন।

• উৎপাদনের ২য় স্থানে রয়েছে যশোর। ২০২৪-২৫ অর্থবছরে উৎপাদন হয় ১২ হাজার ৫৫৩ মেট্রিক টন ড্রাগন। আর তৃতীয় শীর্ষ জেলা রাজশাহীতে উৎপাদন হয় ৪ হাজার ৪৭৭ মেট্রিক টন ড্রাগন।

⇒ ড্রাগন ফল মূলত আমেরিকার প্রসিদ্ধ একটি ফল যা বর্তমানে আমাদের দেশেও ব্যাপক জনপ্রিয়তা অর্জন করেছে। বাংলাদেশে সর্বপ্রথম ২০০৭ সালে থাইল্যান্ড, ফ্লোরিডা ও ভিয়েতনাম থেকে এই ফলের বিভিন্ন জাত আনা হয়। ড্রাগন ফলের গাছ এক ধরনের ক্যাকটাস জাতীয় গাছ। এই গাছের কোন পাতা নেই। ড্রাগন ফলের গাছ সাধারনত ১.৫ থেকে ২.৫ মিটার পর্যন্ত লম্বা হয়ে থাকে।

⇒ বর্তমানে বাংলাদেশ কৃষি গবেষণা ইন্সিটিউট (বারি) কতৃক উদ্ভাবিত ড্রগন ফলের নতুন জাতটি হলো বারি ড্রাগন ফল-১ যা দক্ষিণ -পূর্ব এশিয়াতে জনপ্রিয় ফল। এ ফলের আকার বড়, পাকলে খোসার রং লাল হয়ে যায় ,শাঁস গাঢ় গোলাপী রঙের, লাল ও সাদা এবং রসালো প্রকৃতির । ফলের বীজগুলো ছোট ছোট কালো ও নরম । একটি ফলের ওজন ১৫০ গ্রাম থেকে ৬০০ গ্রাম পর্যন্ত হয়ে থাকে।

উৎস: i) প্রথম আলো।
ii) কৃষি বাতায়ন।

OIC:
- ইসলামিক সহযোগিতা সংস্থা OIC.
- OIC এর পূর্ণরূপ The Organisation of Islamic Cooperation.
- ইসরাইল কর্তৃক আল আকসা মসজিদে আগুন ধরিয়ে দেওয়ার প্রেক্ষাপটে OIC গঠিত হয়।
- এটি মুসলিম দেশগুলোর একটি রাজনৈতিক জোট যা রাবাত সম্মেলনের মাধ্যমে গঠিত হয়।
- প্রতিষ্ঠার স্থান: মরক্কো।
- প্রতিষ্ঠিত হয়: ২৫ সেপ্টেম্বর, ১৯৬৯ সালে।
- সদর দপ্তর: জেদ্দা, সৌদি আরব।
- বর্তমান মহাসচিব: হুসাইন ইব্রাহিম তাহা (১২ তম)। (অক্টোবর, ২০২৫)
- মহাসচিবের মেয়াদ: ৫ বছর।
- অফিসিয়াল ভাষা: তিনটি (আরবি, ইংরেজি, ফ্রেঞ্চ)।
- বর্তমান সদস্য: ৫৭টি। (অক্টোবর, ২০২৫)

⇒ দক্ষিণ আমেরিকা অঞ্চলের দুটি দেশ OIC এর সদস্য।
• গায়ানা ও
• সুরিনাম।

- ইউরোপ মহাদেশের আলবেনিয়া OIC এর সদস্য।
- বাংলাদেশ ১৯৭৪ সালের ২২-২৪ ফেব্রুয়ারি পাকিস্তানের লাহোরে অনুষ্ঠিত OIC এর দ্বিতীয় শীর্ষ সম্মেলনে সর্বপ্রথম অংশগ্রহণ করে।

তথ্যসূত্র - OIC অফিসিয়াল ওয়েবসাইট।

কার্টাগেনা প্রটোকল (Cartagena Protocol):
- কার্টাগেনা প্রোটকলের পূর্ণনাম - The Cartagena Protocol on Biosafety to the Convention on Biological Diversity.
- কার্টাগেনা প্রটোকল জৈব-নিরাপত্তা বিষয়ক একটি আন্তর্জাতিক চুক্তি।
- এই চুক্তিটি কলম্বিয়ার কার্টাগেনাতে আলোচিত হয়।
- চুক্তি অনুমোদন - ২৯ জানুয়ারি, ২০০০ সাল।
- চুক্তি কার্যকর - ১১ সেপ্টেম্বর, ২০০৩ সাল।

তথ্যসূত্র - কনভেনশন অন বায়ো-ডাইভার্সিটি (CBD) ওয়েবসাইট।

জাতিসংঘ:
- জাতিসংঘের অর্থনৈতিক ও সামাজিক কমিশন (ECOSOC) এর অধীন ৫টি আঞ্চলিক কমিশন রয়েছে।

⇒ এগুলো হলো:
- এশিয়া ও প্রশান্ত মহাসাগরীয় অর্থনৈতিক ও সামাজিক কমিশন (ESCAP),
- পশ্চিম এশীয় অর্থনৈতিক ও সামাজিক কমিশন (ESCWA),
- ল্যাটিন আমেরিকা ও ক্যারিবীয় অর্থনৈতিক কমিশন (ECLAC),
- ইউরোপিয়ান অর্থনৈতিক কমিশন (ECE),
- আফ্রিকান অর্থনৈতিক কমিশন (ECA).

তথ্যসূত্র - UN ওয়েবসাইট।

ইউরোপীয় ইউনিয়ন (EU):
- বিশ্বের সবচেয়ে বড় অর্থনৈতিক জোট ইউরোপীয় ইউনিয়ন (EU)।
- এর সদর দপ্তর বেলজিয়ামের ব্রাসেলসে অবস্থিত।
- প্রতিষ্ঠাতা সদস্য: ৬টি দেশ।
- বেলজিয়াম, ফ্রান্স, জার্মানি, ইতালি, লুক্সেমবার্গ, নেদারল্যান্ডস।
- বর্তমান সদস্য: ২৭টি দেশ। (অক্টোবর, ২০২৫)
- সর্বশেষ সদস্য: ক্রোয়েশিয়া। (অক্টোবর, ২০২৫)
- সর্বশেষ ত্যাগকারী: ব্রিটেন (৩১ জানুয়ারি, ২০২০)।
- এটি ১৯৯৩ সালের ১ নভেম্বরে মাসট্রিচট চুক্তি স্বাক্ষরের মাধ্যমে প্রতিষ্ঠিত হয়েছিল।
- তখন থেকে এটি বিশ্বের বৃহত্তম ট্রেডিং ব্লকে পরিণত হয়।

তথ্যসূত্র - EU ওয়েবসাইট।

‘অপারেশন রাইজিং লায়ন':
- ইসরায়েল কর্তৃক ইরানে চালানো সামরিক অভিযানটির নাম 'অপারেশন রাইজিং লায়ন'।
- 'রাইজিং লায়ন' নামটি বাইবেলের একটি অনুচ্ছেদে সিংহের প্রতীকী পরাক্রমকে তুলে ধরে, ইসরায়েলের যুদ্ধ প্রস্তুতি এবং আত্মবিশ্বাসের প্রতীক।
- ১৩ জুন ২০২৫-এর ভোরে ইসরায়েলি বিমান বাহিনী ও গোয়েন্দা সংস্থা মোসাদ যৌথভাবে 'অপারেশন রাইজিং লায়ন' পরিচালনা করে।
- ইসরায়েল প্রথমে 'ড্রোন' দ্বারা ইরানের আকাশ প্রতিরক্ষা ব্যবস্থা দুর্বল করা, এরপর প্রধান পারমাণবিক ও সামরিক লক্ষ্যবস্তুতে বিমান হামলা করে।

উল্লেখ্য:
- এই হামলার জবাবে ইরান পাল্টা হামলা চালায়।
- এই হামলার নাম দেয়া হয় 'অপারেশন টু প্রমিজ থ্রি’।
- ইরান পাল্টা জবাবে শতাধিক ক্ষেপণাস্ত্র ও ড্রোন ছুড়ে।

তথ্যসূত্র - পত্রিকার রিপোর্ট।

IUCN:
- বিশ্ব জীববৈচিত্র্য সংরক্ষণবাদী সংস্থা (IUCN)।
- IUCN এর পূর্ণরূপ - International Union for the Conservation of Nature.
- প্রতিষ্ঠিত হয়: ১৯৪৮ সালে।
- সদর দপ্তর: গ্লান্ড, সুইজারল্যান্ড।
- এটি নিয়ে বিশ্বের ১৭০ টির অধিক দেশ কাজ করছে।
- উদ্দেশ্য: বিশ্বব্যাপী প্রাকৃতিক সম্পদ সংরক্ষণ করা।

তথ্যসূত্র - IUCN অফিসিয়াল ওয়েবসাইট।

IMF:
- IMF এর পূর্ণরূপ The International Monetary Fund.
- এটি আন্তর্জাতিক মুদ্রা তহবিল।
- প্রতিষ্ঠিত হয়: ১৯৪৪ সাল।
- সদর দপ্তর: ওয়াশিংটন ডিসি, যুক্তরাষ্ট্র।
- প্রতিষ্ঠাতা সদস্য: ৪৪টি।
- বর্তমান সদস্য: ১৯১টি। (অক্টোবর, ২০২৫)
- সর্বশেষ সদস্য: লিচেনস্টাইন। (অক্টোবর, ২০২৫)
- বর্তমান ব্যবস্থাপনা পরিচালক: ক্রিস্টালিনা জর্জিয়েভা। (অক্টোবর, ২০২৫)
- বাংলাদেশ সদস্যপদ লাভ করে: ১৯৭২ সালে।

তথ্যসূত্র - IMF অফিসিয়াল ওয়েবসাইট।

প্রশ্ন: P হচ্ছে Q এর পিতা কিন্তু Q, P এর ছেলে নয়। তাদের সম্পর্কটা কোন ধরনের?

সমাধান:
যেহেতু, P হচ্ছে Q এর পিতা কিন্তু Q, P এর ছেলে নয় সুতরাং Q হলো মেয়ে এবং P হচ্ছে পিতা।

সুতরাং, তাদের সম্পর্কটা মেয়ে-পিতা।

প্রশ্ন: নিচের চিত্রে কয়টি ত্রিভুজ আছে?

সমাধান:

একটি করে ফাঁকা ঘর নিয়ে ত্রিভুজ আছে - 1, 2, 3, 4, 5, 6, 7, 8 = ৮ টি
দুইটি করে ফাঁকা ঘর নিয়ে ত্রিভুজ আছে - 12, 34, 56, 78, 67, 58 = ৬ টি
চারটি করে ফাঁকা ঘর নিয়ে ত্রিভুজ আছে - 1267, 3456 = ২টি
সবগুলো ফাঁকা ঘর নিয়ে ত্রিভুজ আছে - 12345678 = ১ টি

সুতরাং, মোট ত্রিভুজ আছে = ৮ + ৬ + ২ + ১ = ১৭ টি

প্রশ্ন: একটি পানি ভর্তি বালতির ওজন ১৪ কেজি। বালতিটি অর্ধেক পানি পূর্ণ থাকলে তার ওজন হয় ৮ কেজি। খালি বালতির ওজন কত?

সমাধান:
দেওয়া আছে,
পানি ভর্তি বালতির ওজন = ১৪ কেজি
অর্ধেক পানি ভর্তি বালতির ওজন = ৮ কেজি
​
​অর্ধেক বালতি পানির ওজন = (১৪ - ৮) কেজি = ৬ কেজি
∴ ​পূর্ণ বালতি পানির ওজন = (৬ × ২) কেজি = ১২ কেজি
​
​আবার,
​পূর্ণ বালতি পানির ওজন + খালি বালতির ওজন = ১৪ কেজি
⇒ ​খালি বালতির ওজন = ১৪ - ​পূর্ণ বালতি পানির ওজন
​⇒ ​খালি বালতির ওজন = ১৪ - ১২ = ২ কেজি

প্রশ্ন: যদি ORANGE = SVERKI হয় তবে GRAPES = ?

সমাধান:
​যদি ORANGE = SVERKI হয় তবে GRAPES = KVETIW
​
​ORANGE শব্দটির বর্ণগুলো থেকে 4 ধাপ এগিয়ে পাওয়া যায়,
O(15) + 4 → S(19)
​R(18) + 4 → V(22)
​A(1) + 4 → E(5)
​N(14) + 4 → R(18)
​G(7) + 4 → K(11)
​E(5) + 4 → I(9)

​অনুরূপভাবে,
GRAPES শব্দটির বর্ণগুলো থেকে 4 ধাপ এগিয়ে গেলে KVETIW শব্দটি পাওয়া যায়। অর্থাৎ,
​G(7) + 4 → K(11)
​R(18) +4 → V(24)
​A(1) + 4 → E(5)
​P(16) + 4 → T(20)
​E(5) + 4 → I(9)
​S(19) + 4 → W(23)
​
অর্থাৎ নির্ণেয় শব্দটি হবে KVETIW

প্রশ্ন: যদি 7 + 3 = 410, 3 + 2 = 15, 6 + 5 = 111 হয়, তবে 8 + 4 = ?

সমাধান:
এখানে
7 + 3 = 410 ⇒ 7 - 3 = 4, 7 + 3 = 10
3 + 2 = 15 ⇒ 3 - 2 = 1, 3 + 2 = 5
6 + 5 = 111 ⇒ 6 - 5 = 1, 6 + 5 = 11

একইভাবে,
8 - 4 = 4, 8 + 4 = 12
সুতরাং, 8 + 4 = 412

প্রশ্ন: A দক্ষিণ দিকে মুখ করে ৪ কি. মি. হাঁটার পর বামদিকে ঘুরল এবং ৫ কি. মি. হাঁটল। আবার ডানদিকে ঘুরে ৮ কি. মি. হাঁটল। এখন যাত্রার স্থান থেকে সরাসরি দূরত্ব কত?

সমাধান:
প্রদত্ত তথ্যগুলোকে চিত্রের মাধ্যমে সাজিয়ে পাই,

এখন, উত্তর-দক্ষিণ দিকে- শুরুতে ৪ কি.মি. দক্ষিণ + পরে আরও ৮ কি.মি. দক্ষিণ = মোট ১২ কি.মি. দক্ষিণ
পূর্ব-পশ্চিম দিকে: শুধু পূর্ব দিকে ৫ কি.মি.

∴ সরাসরি দূরত্ব = √(১২^২ + ৫^২) = √(১৪৪ + ২৫)
= √১৬৯
= ১৩ কি.মি.

প্রশ্ন: (A) চিত্রটির আয়নায় প্রতিবিম্ব কেমন হবে?

সমাধান:


সুতরাং, সঠিক উত্তর (2) নং

Weber's Line is a significant biogeographical boundary in Southeast Asia, proposed by the German naturalist Max Carl Wilhelm Weber. It runs to the east of the more famous Wallace Line, through the Malay Archipelago, between the islands of Sulawesi and New Guinea

The Wallace Line is an invisible boundary that runs through the Indonesian archipelago, separating the fauna of Asia from that of Australasia. Species found to the west of this line are related to Asiatic species and include many placental mammals.

The embryo implants in the endometrium, which is the lining of the uterus. The process of the embryo attaching to the uterine wall is known as implantation or nidation.

In rural Bangladesh, a significant barrier to birth control usage is the limited autonomy of women and the dominant role of men in family planning decisions. This issue is rooted in patriarchal social norms, which are compounded by other factors like fear of side effects, misconceptions, poor access to health services, and religious objections

he Oriental zoogeographical region is also called the Indo-Malayan region.
This region includes the tropical parts of Asia, encompassing:
India
Southeast Asia
The Philippines
Parts of Indonesia west of the Wallace Line, including Sumatra, Java, and Borneo

The term gastrula is derived from the Greek word gaster, meaning 'stomach'; gastrulation therefore implies segregation of gastrodermal from ectodermal cells and establishment of two functionally different cell layers and of the future digestive area.

Gastrulation occurs during the third week of human embryonic development. During this crucial process, the embryo is transformed from a two-layered bilaminar disc into a three-layered gastrula with the primary germ layers: the ectoderm, mesoderm, and endoderm.

The liver originates primarily from the endoderm germ layer, specifically the ventral foregut endoderm, and also receives important signals from the nearby mesoderm. During embryonic development, the endoderm forms the primitive gut tube, from which the liver bud then develops into the mature organ

- Epiboly is a fundamental process of embryonic development where a sheet of cells, or blastoderm, spreads and thins to envelop the entire embryo. This morphogenetic movement is essential for gastrulation, covering the developing organism with a protective layer and internalizing the yolk cell.

Discoidal cleavage is a type of meroblastic (incomplete) cleavage that occurs in animals whose eggs contain a large amount of yolk. It is a characteristic feature of telolecithal eggs, where the yolk is concentrated at one end of the cell.
The organisms that exhibit discoidal cleavage include:
Birds: The large, yolky egg of a chicken, for example, undergoes discoidal cleavage.
Reptiles: This includes crocodiles, snakes, and lizards.
Fish: Many species of fish have eggs with a high yolk content, leading to discoidal cleavage.
Monotremes: These egg-laying mammals, such as the echidna and platypus, also undergo discoidal cleavage

The most devastating pest of jute, known as the "jute hairy caterpillar," is Spilosoma obliqua. It is widely considered the most destructive insect to jute crops.
Scientific name: Spilosoma obliqua.
Devastating larval stage: The caterpillar, or larval stage, feeds voraciously on jute leaves and soft stems, often skeletonizing or completely defoliating the plant.
Damage: Heavy infestations can significantly reduce the yield and quality of the fiber.

The rice weevil (Sitophilus oryzae) is a primary pest that causes significant damage to stored rice grains, as its larvae develop and feed entirely within the kernel. Other major pests include the Angoumois grain moth and the lesser grain borer, which also infest and damage the grain from the inside out, leading to substantial losses in quality and quantity.

The sugarcane variety Isd 36 showed the highest resistance to stem borer infestation in Bangladesh, recording the lowest infestation levels in a study conducted by the Bangladesh Sugarcane Research Institute (BSRI) in 2009-2010, according to Journal SAU.

According to a 2024 government survey, the Royal Bengal Tiger population in the Bangladesh Sundarbans is 125. The tiger census, announced in October 2024 by the Forest Department, found that the number of tigers has increased by 11 since the last survey in 2018, when the population was 114

LC LEAST CONCERN
VN- VULNERABLE
EN- ENDANGERED
CE-CRITICALLY ENDANGERED

The Hispid hare is sometimes called the Assam rabbit or bristly rabbit. The "bristly rabbit" nickname comes from its harsh, bristly fur coat.

বাংলাদেশ বন্যপ্রাণী (সংরক্ষণ ও নিরাপত্তা) আইন, ২০১২ এর ধারা ৪৮ অনুযায়ী গবেষণা ও পর্যবেক্ষণের জন্য কোনো ব্যক্তি বা সংস্থা প্রধান ওয়ার্ডেন বা তাঁর ক্ষমতাপ্রাপ্ত কর্মকর্তার কাছ থেকে অনুমতি নিতে হবে।
এই ধারায় বলা হয়েছে যে, কোনো ব্যক্তি, সংস্থা বা প্রতিষ্ঠান যদি কোনো বন্যপ্রাণী বা বন্যপ্রাণীর আবাসস্থল নিয়ে গবেষণা করতে চায়, তাহলে তাকে অবশ্যই বন্যপ্রাণী সংরক্ষণ ও নিরাপত্তা আইন, ২০১২ অনুযায়ী প্রধান ওয়ার্ডেন বা তাঁর অনুমোদিত কোনো কর্মকর্তার নিকট থেকে অনুমতি নিতে হবে।
বন্যপ্রাণী (সংরক্ষণ ও নিরাপত্তা) আইন, ২০১২ | ৪৮। বৈজ্ঞানিক গবেষণা
Jul 10, 2012 — ৪৮। কোন ব্যক্তি, সংস্থা বা প্রতিষ্ঠান কোন বণ্যপ্রাণী বা বন্যপ্রাণীর আবাসস্থল বিষয়ে গবেষণা করিতে ইচ্ছুক হইলে প্রধান ওয়ার্ডেন বা তৎকর্তৃক ক্ষমতাপ্রাপ্ত কোন কর্মকর্তার নিকট হইতে অনুমতি গ্রহণ করিতে হবে।

একটি বাস্তুতন্ত্রে শক্তি প্রবাহের ধরন সর্বদা একমুখী হয়, যা সূর্য থেকে শুরু হয়ে খাদ্য শৃঙ্খল বা খাদ্য জালের মাধ্যমে এক স্তর থেকে অন্য স্তরে প্রবাহিত হয় এবং শক্তি হারিয়ে যায়, কখনোই ফিরে আসে না। উৎপাদক যেমন সবুজ উদ্ভিদ সূর্যালোক থেকে শক্তি গ্রহণ করে এবং তাকে রাসায়নিক শক্তিতে রূপান্তরিত করে, যা পরবর্তীতে তৃণভোজী এবং মাংসাশী প্রাণীদের মধ্যে স্থানান্তরিত হয়। এই প্রক্রিয়ায় প্রতিটি স্তরে শক্তির অপচয় হয় এবং শেষ পর্যন্ত তাপশক্তি হিসেবে পরিবেশে ফিরে আসে, যার ফলে শক্তি প্রবাহের একটি ধারাবাহিক দিকনির্দেশনা বজায় থাকে।

The "Phytoplankton → snails → snakes" example is a grazing food chain that exists within an aquatic ecosystem
Pond plants: These are the producers. They create their own food and energy through photosynthesis using sunlight. They form the base of the grazing food chain.
Snails: These are the primary consumers (herbivores). They eat the living pond plants, transferring the energy from the producers up the food chain.
Snakes: These are the secondary consumers (carnivores or omnivores). They prey on the snails, continuing the flow of energy.

Grazing vs. Detritus food chains
The key distinction that makes this a grazing food chain, as opposed to a detritus food chain, is that the initial energy comes from living plants.
Grazing food chain: Energy flows from living plants (producers) to herbivores (primary consumers) and then to carnivores.
Detritus food chain: Energy starts with dead organic matter (detritus), which is eaten by decomposers and detritivores, and then by predators

A heterotroph is an organism that cannot produce its own food and must obtain energy and nutrients by consuming other organic material. This means all heterotrophs, also called consumers, rely on other organisms for their sustenance.

Pancreatic juice contains enzymes that break down carbohydrates (amylase), fats (lipase), and proteins (proteases like trypsin and chymotrypsin), as well as nucleases that digest nucleic acids. These enzymes, which are secreted in an inactive form, are essential for digestion in the small intestine, neutralizing stomach acid and allowing for nutrient absorption.

The blastula of Amphioxus is known as a coeloblastula.
Key characteristics of a coeloblastula include:
It is a simple, hollow blastula.
It consists of a single layer of cells, called the blastoderm.
The cells surround a central, fluid-filled cavity known as the blastocoel.

The outer cell mass of the blastocyst that interacts with the endometrium during implantation is called the trophoblast.
During implantation, this outer layer performs several vital functions:
Attachment to the uterine wall: After the blastocyst "hatches" from its outer shell (the zona pellucida), the trophoblast adheres to the uterine lining (endometrium).
Placenta formation: The trophoblast differentiates further into two layers—the cytotrophoblast and syncytiotrophoblast—which develop to form the fetal portion of the placenta.
Secretion of hormones: The trophoblast secretes human chorionic gonadotropin (hCG), the hormone detected by pregnancy tests, which maintains the corpus luteum and ensures the continued production of progesterone to sustain the pregnancy.
Nutrient and gas exchange: Once the placenta is formed, the trophoblast facilitates the transfer of oxygen and nutrients from the mother to the embryo and removes waste products.

In the absence of fertilization, the corpus luteum degenerates and transforms into a scar-like tissue called the corpus albicans. This process, known as luteolysis, typically occurs about 10–14 days after ovulation.

The net gain of ATP molecules from one glucose molecule in glycolysis is two
ATP used: In the initial, "energy-investment" phase of glycolysis, two molecules of ATP are consumed to start the process.
ATP produced: In the later "energy-payoff" phase, four molecules of ATP are generated through a process called substrate-level phosphorylation.
Net gain: The overall gain is calculated by subtracting the two ATP molecules used from the four ATP molecules produced ( 4−2=24 minus 2 equals 2
4−2=2

Excess amino acids in the body are primarily broken down and converted into glucose or fat for energy or storage. The body cannot store excess amino acids in the same way it stores fat or carbohydrates.

Deamination
The first step is deamination, where the amino ( −NH2negative NH sub 2
−NH2
) group is removed from the amino acids. This process produces two components:

A toxic waste product: Ammonia ( NH3NH sub 3
NH3
), which the body must quickly neutralize.
An organic molecule: A carbon skeleton, also known as a keto acid.
Nitrogen excretion (Urea cycle)
The liver converts the toxic ammonia into a much less harmful compound called urea. The urea is then released into the bloodstream, transported to the kidneys, and excreted from the body in urine.

Key ecotourism areas in Bangladesh include the Sundarbans, a massive mangrove forest and UNESCO World Heritage Site, the Sylhet region with its tea estates and rainforests, and the Chittagong Hill Tracts, which offer rich biodiversity and tribal cultures. Other significant sites are the Ratargul Swamp Forest, Tanguar Haor wetland, and Nijhum Dwip, promoting community-based and eco-friendly tourism practices

- The probability of getting a homozygous dominant (AA) offspring from two heterozygous (Aa x Aa) parents is 1/4 or 25%. This is because each parent can pass on either the 'A' or 'a' allele, and when two heterozygous parents cross, the only way to get the 'AA' genotype is if both parents contribute the 'A' allele, resulting in one of the four equally likely combinations from a Punnett square.

When two genes are very close on a chromosome, their recombination frequency is very low, approaching 0%. This means the genes are tightly linked and are very likely to be inherited together during meiosis

The correct arrangement of genes on a chromosome can be determined using a combination of techniques known as gene mapping. The two primary approaches are genetic (linkage) mapping and physical mapping

The sequence of three nucleotides on mRNA that codes for a specific amino acid is called a codon
Decoding genetic information: During protein synthesis, the ribosome reads the mRNA sequence in groups of three nucleotides. Each three-nucleotide sequence is a codon.
Universal code: There are 64 possible codons, 61 of which specify one of the 20 amino acids. The remaining three are "stop" codons that signal the end of translation.
The start codon: The codon AUG serves as the start signal for translation and also codes for the amino acid methionine.

The energy needed for peptide bond formation during translation is mainly provided by the hydrolysis of guanosine triphosphate (GTP). This process is managed by elongation factors (EFs) that utilize GTP to drive the steps of translation.

Transcription of mRNA begins at a specific sequence on DNA called the promoter.
Here is how it works:
Binding site: The promoter is a region of DNA located near the beginning of a gene that acts as a binding site for the enzyme RNA polymerase.
initiation: In the first step of transcription (initiation), RNA polymerase and other necessary proteins bind to the promoter.
Directionality: The promoter region provides the correct orientation for the RNA polymerase, signaling the direction of transcription and indicating which DNA strand should be copied.
Start site: The transcription start site is typically located a short distance away, "downstream" from the promoter, at which point the actual synthesis of the mRNA molecule begins.

The process that removes non-coding regions (introns) from pre-mRNA is called RNA splicing. This process, which occurs in eukaryotic cells, joins the remaining coding regions (exons) together to form a mature messenger RNA (mRNA) molecule.

DNA replication occurs during the S (Synthesis) phase of the cell cycle. This phase is part of a longer preparatory period called interphase, which takes place before the cell divides
Here is how the S phase fits into the overall cell cycle for eukaryotes:
Interphase: This is the longest part of the cell cycle, during which the cell grows and prepares for division. It consists of three sub-phases:G1 (First Gap) Phase: The cell grows, copies its organelles, and accumulates the molecular building blocks and energy reserves needed for DNA replication.
S (Synthesis) Phase: The cell duplicates its entire genome. After this phase, each chromosome consists of two identical sister chromatids.
G2 (Second Gap) Phase: The cell grows more, synthesizes proteins, and prepares for mitosis.
M (Mitotic) Phase: Following interphase, the cell enters this phase to divide. It consists of two tightly coupled processes:Mitosis: The cell's nucleus divides, and the sister chromatids are pulled apart into two identical sets of chromosomes.
Cytokinesis: The cytoplasm is divided, completing the formation of two new daughter cells.

DNA replication starts at specific sites called origins of replication. The replication process begins at these locations when initiator proteins bind to the DNA and begin to unwind it
Prokaryotes vs. eukaryotes: Prokaryotes (like bacteria) typically have a single origin of replication on their circular chromosome. Eukaryotes (like humans) have much larger linear chromosomes and use multiple origins to speed up the process.
Replication forks: The unwinding of DNA at the origin creates a replication bubble with two Y-shaped structures called replication forks, where the DNA is actively copied. The forks then move away from the origin in opposite directions, a process known as bidirectional replication.
Composition: Origins are often rich in adenine (A) and thymine (T) base pairs, which are held together by fewer hydrogen bonds than guanine (G) and cytosine (C). This makes the DNA strands at these sites easier to separate

RNA can fold back on itself to form various secondary structures through intramolecular base pairing. These structures are crucial for RNA's biological functions, stability, and recognition by other molecules.
Common RNA secondary structures include:
Hairpin (or stem-loop): A very common structure where a single RNA strand folds back on itself. A sequence of nucleotides pairs with a reverse-complementary sequence downstream to form a double-helical "stem," with a single-stranded "loop" connecting the two paired regions.

In RNA, the nucleotide sequence is synthesized in the 5′ to 3′ direction. This process is carried out by RNA polymerase, which adds new nucleotides to the 3′ end of the growing RNA chain, using a DNA template strand that is read in the 3′ to 5′ direction.

The two strands of the DNA double helix are held together by hydrogen bonds. These bonds form between the complementary nitrogenous bases of each strand

Birds that cannot fly, known as flightless birds, include well-known examples like ostriches, emus, kiwis, and penguins, along with others such as cassowaries, rheas, and the flightless cormorant. These birds have lost the ability to fly through evolution, often due to lacking a keel on their sternum for flight muscle attachment or having heavy bodies ill-suited for flight, as seen in the ratites (ostriches, emus, kiwis, cassowaries, and rheas)

Kiwi birds are native only to New Zealand, where they live in a variety of habitats, including forests, scrubland, and grasslands. This nocturnal, flightless bird is the national symbol of New Zealand and is found across the North and South Islands

The bead-like structure formed by DNA and histone proteins is called a nucleosome, the fundamental repeating unit of chromatin. This compact arrangement allows the vast amount of DNA in a eukaryotic cell to be organized and packaged within the nucleus. When observed with an electron microscope, a string of nucleosomes resembles "beads on a string"

যে প্রক্রিয়ায় জিনগতভাবে অভিন্ন অপত্য কোষ তৈরি হয় তার নাম হলো মাইটোসিস (Mitosis)। এই প্রক্রিয়াটিতে একটি মাতৃকোষ তার ক্রোমোজোম সহ সমস্ত উপাদান প্রতিলিপি করে এবং তারপর দুটি জিনগতভাবে অভিন্ন কন্যা কোষে বিভক্ত হয়, যেখানে ক্রোমোজোমের সংখ্যা মূল কোষের সমান থাকে

In humans, an acrocentric chromosome has the centromere located very near one end, which creates a very short p arm and a long q arm.
In contrast, other types of chromosomes have their centromeres closer to the center.
The five pairs of human acrocentric autosomes are chromosomes 13, 14, 15, 21, and 22. The Y chromosome is also acrocentric

Crossing over is part of the larger meiotic division that produces gametes (sperm and egg cells). It involves several steps within prophase I, including:
Leptotene: Chromosomes begin to condense and become visible.
Zygotene: Homologous chromosomes pair up side-by-side in a process called synapsis. A protein structure called the synaptonemal complex holds them together.
Pachytene: Crossing over occurs. Segments of genetic material are exchanged between the non-sister chromatids of the homologous chromosomes.
Diplotene: The synaptonemal complex breaks down, but the homologous chromosomes remain attached at the sites where crossing over occurred. These connections are known as chiasmata.

A set of chromosomes in a nucleus of a species is usually called a genome. A genome is the complete set of an organism's genetic material, or DNA

Bird wings, whale flippers, cat forelegs, and human hands are examples of homologous structures, which are organs with a similar underlying bone structure that evolved from a common ancestor but now serve different functions.

The Golgi apparatus is a membrane-bound organelle composed primarily of flattened, stacked sacs called cisternae. It also includes associated vesicles and interconnected tubular structures.

Centrioles, located within the centrosome near the nucleus in animal cells, are primarily involved in cell division and the formation of cilia and flagella. They serve as the main microtubule-organizing centers (MTOCs) of the cell

The cell membrane, also known as the plasma membrane, is often called the "security guard" of the cell. It controls what enters and exits the cell, maintaining the cell's internal environment

The phylum that includes animals that are mostly asymmetrical and have a body supported by spicules or spongin fibers is Porifera. This group is commonly known as sponges.

Animals with stinging cells called cnidocytes and radial symmetry belong to the phylum Cnidaria. This group includes familiar aquatic animals such as jellyfish, corals, and sea anemones

The class of the phylum Arthropoda characterized by animals with three pairs of legs and a pair of antennae is Insecta.
This class is part of the larger subphylum Hexapoda, which literally means "six legs".
Key features of insects:
Body segments: Their bodies are divided into three parts: a head, a thorax, and an abdomen.
Legs: The thorax bears three pairs of jointed legs, giving rise to the name hexapod (six legs).
Antennae: The head has a single pair of antennae, which are used for sensory purposes.
Other features: Many insects also have one or two pairs of wings attached to the thorax, making them the only invertebrates capable of flight.

The phylum Annelida is best characterized by a body plan that is segmented, bilaterally symmetrical, and has a true body cavity called a coelom. This metameric segmentation, or repetition of body parts, is the most distinctive feature of the phylum and is visible both externally and internally.

Animals with a soft body, a calcium carbonate shell, a muscular foot, and a radula belong to the phylum Mollusca. This phylum is incredibly diverse, encompassing creatures like snails, clams, and squids, and includes a soft mantle that secretes the shell, the visceral mass containing organs, and a muscular foot used for movement.

An endemic species is a species of plant or animal that naturally exists and is found only in a specific geographic area, such as an island, a mountain range, or a lake, and nowhere else in the world. These unique species contribute significantly to the planet's biodiversity but are often vulnerable and at a greater risk of extinction.

Porifera (sponges) reproduce asexually through budding, fragmentation, and the formation of gemmules.
Sponges can also reproduce sexually
Budding
External buds A small outgrowth, or bud, develops on the parent sponge's body.
Detachment This bud can remain attached to the parent, forming a colony, or detach and grow into a new, genetically identical sponge
Fragmentation
Breaking off A piece of the parent sponge breaks off, often due to physical damage.
Regeneration Because sponges are not "cephalized"—meaning they have no distinct head or body systems—the fragment has all the necessary cells and tissue to settle on a surface and grow into a new, identical sponge
Gemmules
Internal buds Gemmules are internal buds, most common in freshwater sponges, that form during harsh conditions.
Protective casing They consist of a cluster of cells surrounded by a tough, protective coating that resists freezing, drying, and oxygen deprivation.
Survival strategy When conditions become favorable again, the gemmules are released, and the cells within them emerge and develop into a new sponge.

The central digestive cavity in cnidarians is called the gastrovascular cavity or coelenteron

Platyhelminthes (flatworms) lack complete respiratory, circulatory, and digestive systems, relying on diffusion for gas exchange and simple nutrient distribution through their branched gut or directly through their body wall in the case of tapeworms. These organisms are acoelomate, meaning they have no body cavity, which contributes to their flat shape and limits their size, as oxygen and nutrients must reach all cells efficiently.

Nematodes (roundworms) possess a pseudocoelom, which is a "false" body cavity. This fluid-filled space lies between the outer body wall and the inner digestive tract but is not fully lined with mesodermal tissue.

Many annelids use a combination of hydrostatic skeletons, muscles, and specialized appendages like parapodia and chaetae to achieve a variety of complex movements. The specific structures used for locomotion vary depending on the annelid's class and lifestyle

Mollusks are typically covered by a hard shell made of calcium carbonate, secreted by a fleshy membrane called the mantle. While some mollusks, like snails, have prominent external shells, others, such as slugs or squids, possess internal or reduced shells.

racheal System: This is a network of tiny tubes that delivers oxygen directly to the tissues and is characteristic of most terrestrial insects, myriapods, and some arachnids.
Gills: Aquatic arthropods, such as crustaceans (e.g., crabs, lobsters, shrimp), use gills to absorb oxygen from the water.
Book Lungs: Many arachnids, including spiders and scorpions, have book lungs, which are internal structures with stacked, leaf-like plates for gas exchange with the air.
Book Gills: These are found in aquatic chelicerates like horseshoe crabs and are layered structures that function similarly to gills.

The class of mollusks with a calcareous shell composed of two hinged parts is Bivalvia. These mollusks are commonly called bivalves and include species such as clams, oysters, scallops, and mussels.
Key characteristics of bivalve shells:
Two valves: The shell consists of two halves, or "valves," that are joined together.
Hinge: The two valves are connected by a flexible ligament and interlocking "teeth" that form a hinge. This hinge allows the shell to open and close without the valves detaching.
Calcium carbonate composition: The valves are secreted by the animal's mantle and are made of calcium carbonate.

Mollusks are associated with several medical applications, notably in the development of pain medication, surgical adhesives, and anticancer and anti-inflammatory agents. Their venoms, secretions, and immune system molecules are rich sources of bioactive compounds with significant pharmaceutical potential.

Pain management
The venom of marine cone snails (genus Conus) contains potent neurotoxins called conotoxins, which are used for prey capture and defense.
Ziconotide (Prialt): This FDA-approved drug for severe chronic pain is a synthetic version of ω-conotoxin MVIIA, isolated from the magical cone snail (Conus magus). It works by blocking N-type calcium channels in the spinal cord to stop pain signals from reaching the brain, and it is administered directly into the spinal fluid.
Neuropathic pain research: Other conotoxins are in clinical trials for treating nerve-related pain conditions like sciatica and diabetic neuropathy
urgical and medical adhesives
Mussels produce special adhesive proteins (MAPs) that allow them to stick to wet surfaces like rocks.
Wound healing: These adhesive proteins are being developed into surgical glues and injectable hydrogels for closing wounds and promoting tissue healing.
Hemostasis: Mussel-inspired adhesives are also used to create hemostatic sealants that quickly stop bleeding during surgery.
Bone and cartilage repair: Researchers have created mussel-inspired adhesive composite hydrogels that can be used to promote bone and cartilage regeneration.
Anticancer agents
Various mollusks produce compounds with antitumor activity, many of which are in clinical trials.
Dolastatins and Auristatins: Peptides originally isolated from the sea hare (Dolabella auricularia) have been modified to create powerful anticancer drugs. The related auristatins are used in antibody-drug conjugates (ADCs) to specifically target and kill cancer cells.
Kahalalide F: This peptide comes from the sea slug (Elysia rufescens) and is being investigated as a potential treatment for certain cancers.
Spisulosine: This compound from the Arctic surf clam (Spisula polynyma) has also been studied for its potential in cancer treatmen

Arthropods play an important role in ecosystems primarily by providing vital ecosystem services, including pollination, decomposition, and acting as a food source for other animals. With over 80% of all animal species, their sheer numbers and diversity enable them to dominate nearly every habitat on Earth
Pollination
Arthropods, particularly insects, are essential for the reproduction of countless plant species.
Bees, butterflies, and beetles transfer pollen between flowers, enabling the fertilization of plants that produce many of the world's fruits, vegetables, and seeds.
Over one-third of the world's food crops depend on animal pollinators, highlighting the immense value of this arthropod-mediated ecosystem service.
Decomposition and nutrient cycling
Many arthropods are detritivores, meaning they feed on and break down dead plants, animals, and waste.
Mites, springtails, millipedes, and beetles help convert organic matter into nutrient-rich soil.
Their feeding and burrowing activities aerate and mix the soil, which enhances its physical properties and fertility.
This process enriches the soil and recycles nutrients, making them available for new plant growth

Pharyngeal gill slits in chordates have two primary functions that vary depending on the species and its stage of development: filter-feeding and respiration. They also have different developmental fates in different chordate groups.

Osteichthyes, commonly known as bony fish, is a superclass of vertebrates that includes the vast majority of all fish species, accounting for over 95% of living fish. Their primary distinguishing feature is a skeleton primarily composed of bone, rather than cartilage like in the Chondrichthyes (sharks and rays). This diverse group inhabits nearly all aquatic environments, from freshwater rivers and lakes to the deep sea.

Chondrichthyes, the class of cartilaginous fish, includes sharks, rays, skates, and chimaeras. Their defining characteristics include a skeleton made of cartilage rather than bone, internal fertilization, and a highly developed sensory system

Mammals are a class of vertebrates distinguished by several unique traits that set them apart from other animals. These characteristics include feeding their young with milk, having hair or fur, possessing a four-chambered heart, and being warm-blooded.
Amphibians are cold-blooded vertebrates that live a "double life," having both aquatic and terrestrial stages in their life cycle. The class includes frogs, toads, salamanders, newts, and caecilians, and its characteristics represent a key evolutionary transition from water to land.

In Obelia colonies, the specialized reproductive zooids are the gonangia (or blastostyles), which are polyps dedicated to asexual budding. These gonangia produce numerous small, free-swimming medusae, which are the sexually reproductive zooids.

Coral reefs are formed primarily by stony corals, which are tiny marine animals called polyps. These polyps secrete calcium carbonate to create a hard, protective exoskeleton. Over thousands of years, as countless generations of polyps reproduce, grow, and die, these skeletons accumulate and build the massive reef structures

In its life cycle, Obelia alternates between the asexual, sessile polyp form and the sexual, free-swimming medusa form. This process is known as metagenesis or alternation of generations.

n conjugation, two Paramecia come together and exchange haploid micronuclei.
This process is a form of sexual reproduction that allows for genetic recombination, increasing the genetic diversity of the offspring

Mature cysts of Entamoeba histolytica and Entamoeba dispar have four nuclei, while those of Entamoeba coli can have eight or more nuclei, making the nuclear count a key differentiator for identifying species. These cysts are hardy, chitin-walled structures, which allow the parasite to survive outside the host's body in the external environment

The infective stage of Eimeria that is ingested by a host is the sporulated oocyst. This resilient, thick-walled spore is shed in the feces of an infected animal and matures in the environment

The average size of an
Eimeria oocyst varies significantly depending on the species and the host it infects. For example, oocyst sizes range from around 10×1010 cross 10
10×10µm for E. subspherica in cattle to 95×7595 cross 75
95×75 µm for E. cameli in camels

The definitive host of Fasciola hepatica is primarily ruminants like cattle, sheep, and goats, though it can also infect humans, wildlife, and other mammals such as equids. The parasite matures into adults within the biliary ducts of the definitive host, where they lay eggs that are then expelled in the feces, leading to the next stage of the parasite's life cycle in the water

The larval form of the pork tapeworm, Taenia solium, found in an intermediate host is called a cysticercus. The scientific name for this larval stage is Cysticercus cellulosae

The definitive host for Ascaris lumbricoides is humans, and the parasite's life cycle is completed in a single host, meaning there is no intermediate host. After ingestion of the parasite's eggs, the larvae migrate to the lungs and then back to the small intestine, where they develop into adult worms and reproduce, thereby continuing the cycle.

The structural adaptation that helps Fasciola hepatica resist the host's digestive enzymes is its resistant tegument. This outermost protective layer, which is a syncytial (multinucleated) layer of cells, is modified to prevent damage from the host's digestive system and also plays a role in nutrient absorption.

The most significant environmental factor favoring the spread of Ascaris lumbricoides is poor sanitation and lack of adequate waste disposal, which leads to human feces contaminating soil, water, and food. This is especially prevalent in tropical and subtropical climates with high temperatures and humidity, which enhance the survival and transmission of the worm eggs

After fertilization, the larva that emerges in Nereis is called a trochophore.
This small, translucent, and free-swimming larval stage is characteristic of many marine annelids and mollusks

In the genus Hirudo (leeches), the cocoon is produced by the clitellum, a specialized, thickened glandular ring in the skin. This structure is characteristic of clitellate annelids, a group that includes earthworms and leeches

The primary mode of feeding for Nereis is best described as opportunistic omnivory, with various species exhibiting different strategies depending on food availability. While many are predators, others are scavengers, deposit feeders, or even filter feeders.
Carnivorous predation: Many species, such as Nereis virens, use a powerful, eversible pharynx equipped with sharp jaws to capture small crustaceans, mollusks, and other invertebrates. They can extend their head out of their burrow to grab passing prey, or even leave the burrow to hunt
Filter feeding: Some species, notably Nereis diversicolor, are known to be facultative filter feeders. While inside their burrow, they secrete a mucus net and then use undulating body movements to pump water through it. Small food particles, like phytoplankton, get trapped in the net, which the worm later ingests.

The hypopharynx in insect mouthparts is functionally similar to a tongue, as it is a tongue-like structure that helps move food during mastication and assists in swallowing. It also functions in distributing saliva and, in some cases, helps absorb water, while also containing chemosensory cells to detect food suitability.

he internal network of tubes that insects use for respiration is called the tracheal system. The main parts of this system are:
Spiracles: The external openings on the insect's body that allow air to enter the system.
Tracheae: The main air tubes that branch throughout the insect's body.
Tracheoles: The smallest branches of the tracheae, which deliver oxygen directly to individual cells

In insects, the Malpighian tubules actively transport potassium ions, sodium ions, and uric acid from the hemolymph (circulatory fluid) into the tubule lumen. Water and other small solutes follow passively to form a potassium-rich pre-urine

Insects with incomplete metamorphosis, also called hemimetabolous insects, include grasshoppers, cockroaches, true bugs, praying mantises, crickets, earwigs, termites, dragonflies, and mayflies. These insects go through three life stages—egg, nymph, and adult—where the nymph gradually grows larger and sheds its skin until it reaches its adult form

The pupa of butterflies is also called a chrysalis. Depending on the species, the pupa may suspended under a branch, hidden in leaves or buried underground. The pupa of many moths is protected inside a coccoon of silk

The prominent anatomical feature used during copulation in male Pila is a rudimentary copulatory organ, often referred to as the penis.
This feature is not a well-developed, complex structure but is functional for transferring sperm during mating

The male Sepia (cuttlefish) uses a specialized arm called the hectocotylus to transfer spermatophores (sperm packets) to the female, typically inserting them into her buccal cavity. This arm is modified in its anatomy to be specialized for holding and transferring the sperm packets.

The outermost organic layer of the molluscan shell is called the periostracum. It is a thin, leathery layer composed of the protein conchiolin

The mollusc product used historically and currently as a luxury dye is Tyrian purple, a vibrant reddish-purple dye extracted from Murex sea snails. Known for its deep, rich color and exceptional durability, it was a status symbol in the classical world, restricted for the elite and bringing great wealth to the Phoenicians. Today, artisans continue to extract it from these marine snails, though it is a rare and expensive commodity

Molluscs contribute to environmental health by filtering water, creating habitats, serving as a food source, and acting as bioindicators to monitor pollution and climate change. Their ability to filter particles helps maintain water quality and clarity, while structures built by mussels and oysters provide crucial habitats for other organisms and protect coastal areas. As they accumulate pollutants, their presence and physiological changes can be used to assess environmental contamination, and their shells offer valuable insights into past climate events.

Astropecten species are characterized by a diverse larval development, producing either free-swimming, feeding bipinnaria larvae or nonfeeding, barrel-shaped larvae that develop directly into juveniles. The specific type of larva produced varies by species, with some producing bipinnaria larvae that go on to develop a brachiolaria stage, while others develop directly from the bipinnaria or from barrel-shaped larvae, a nonbrachiolarian type of development.

Astropecten, like other members of the class Asteroidea (sea stars), exhibits both sexual and asexual reproduction
Sexual reproduction
Astropecten primarily reproduces sexually through a process called spawning.
Separate sexes: In most cases, individuals are either male or female, a condition known as gonochorism.
External fertilization: Mature Astropecten release their gametes (sperm and eggs) directly into the water column.
Planktonic larvae: After fertilization, the resulting embryos hatch into planktonic larvae, which drift in the ocean before settling on the seafloor and developing into juvenile sea stars.
Seasonal spawning: The timing of spawning can be influenced by environmental factors such as water temperature and food availability.

Asexual reproduction
Astropecten and other sea stars are also capable of reproducing asexually through regeneration
Fissiparity and autonomy: This process typically involves the animal splitting into two or more parts, with each part regenerating into a new, genetically identical individual. For this to occur, a portion of the central disc must be present in the severed section.
Regeneration: While this ability is mainly a mechanism for recovery from injury, it can also function as a form of reproduction.

Typical sea urchins have five gonads, which are the reproductive organs where either sperm or eggs are produced. These five gonads are arranged between the ambulacral grooves, where the tube feet emerge, and they serve as the main storage site for nutrients in addition to reproduction

a remarkable furrow line in each arm known as ambulacral groove extending from the peristome to the tip of the rays. These grooves are formed by series of plates or ossicles known as ambulacral plates which has ambulacral pores between it through in which podia held.

The madreporite is the structure that allows water to enter the water vascular system of echinoderms

Labeo rohita has an inferior (sub-terminal) mouth with thick, fringed lips. It also has two pairs of barbels, with the fleshy lips and their specialized structure adapted for its feeding behavior

In Ascidia, the atriopore is located in the middle of the atrial or excurrent siphon.
The atrial siphon is the opening through which water, waste, and gametes are expelled from the animal's body