IBA ফ্যাকাল্টি ভিত্তিক প্রস্তুতি
The appearance
P: dinosaurs were at their peak
Q: of the first mammals on the earth
R: at the time when
S: went almost unnoticed
P: dinosaurs were at their peak
Q: of the first mammals on the earth
R: at the time when
S: went almost unnoticed