Contrast the structure of a bastula with that of a gastrula?

Blastocyst,Blastoderm

Explanation:

The blastula is made up of a hollow spherical layer of cells, referred to as the blastoderm which surrounds a yolk or fluid-filled space called the blastocele or blastocoel. In most mammals, including humans, the structure formed next is the blastocyst, a mass of inner cells that are distinct from the blastula

to this one it would be receptive field