Question

what is the process by which blastulas are formed through a series of cell divisions?
differentiation
cleavage
fertilization
gastrulation

Explanation:

Cleavage is the series of rapid cell - divisions that transform the zygote into a blastula. Differentiation is about cells becoming specialized, fertilization is the union of gametes, and gastrulation is the formation of the gastrula from the blastula.

Answer:

B. Cleavage