The epiblast plays a crucial role in early mammalian embryogenesis.

Mammals can maintain a constant body temperature.

The process of embryogenesis is very complex, with continuous cell division and differentiation.

The blastoderm is formed in the early stages of embryonic development.

The development process of the embryo is very complex.

The development process of an embryo is very complex.

The blastula stage is an early stage where the fertilized egg divides and becomes a cell with many cells.

Germ cells play an important role in the reproduction of organisms.

I picked up the leaves that were falling in the park.

The upper level of this building has high-end restaurants and offices.