Question

the outer ring of cells of the blastocyst makes up the ___________, which will become the chorion.
a inner cell mass
b embryonic disk
c trophoblast
d amnion

Explanation:

The blastocyst has an outer layer of cells. The trophoblast is this outer - ring layer. The inner cell mass is the inner group of cells (not the outer ring). The embryonic disk is part of the inner cell mass. The amnion is a membrane that forms later around the embryo, not the outer ring of the blastocyst. The trophoblast will develop into the chorion (an extra - embryonic membrane).

Answer:

C. trophoblast