When Does a Zygote Become a Multicellular Creature

Question

When does a zygote become a multicellular creature?
A) at fertilization
B) when cleavage begins
C) when organs begin to form
D) when the heart begins beating
E) at birth

Accepted Answer

A zygote becomes a multicellular creature when cleavage begins, as this is the process where the single-celled zygote starts dividing to form multiple cells.