Question

What is trophoblast?

Answer 1

Trophoblast is the outer covering of blastula i.e. of embryo which is at 64 celled stage. The embryo is known as blastocyst. It comprises of an inner cell mass which is attached to embryonic pole and an outer covering of cells which is known as trophoblast. The trophoblast later forms the chorion which is part of placenta.