Question

why do a chicken embryo and a cow embryo look very similar even though the adults do not?
they are not related, but still have similar development.
they are distantly related, so their development is similar.
the embryos mutate in utero to form different structures.
the genetic makeup of the two species changes during development.

Explanation:

Chicken and cow embryos share similar early development because they are distantly related vertebrates, inheriting common developmental pathways from a shared ancestor. As development proceeds, species-specific traits emerge, leading to different adult forms. The other options are incorrect: they are related (not unrelated), embryos do not mutate in utero to form different structures, and genetic makeup remains constant during development.

Answer:

They are distantly related, so their development is similar.