Which observation provides the best evidence that two different animals have a common ancestor?

Question

a
Both have similarities in early embryonic development.
b
Both inhabit the same environment.
c
Both use sexual reproduction to produce offspring.
d
Both choose the same plants for food.

Answer 1

The best evidence that two different animals have a common ancestor is if both have similarities in early embryonic development (a). This indicates that they share similar genetic and developmental pathways that can be traced back to a common ancestor.