Question

how can evolutionary relationships among organisms be determined by comparing embryonic development?
a embryos retrace their ancestral stages during embryonic development.
b embryos of more closely related organisms show greater similarities in development.
c embryos that develop inside eggs lack similarities to placental mammals.
d both fish and humans have a two chambered heart in an early stage of development.

Explanation:

Embryonic development similarities can indicate evolutionary relationships. Option B is correct as more closely related organisms generally show greater similarities in embryonic development. Option A is incorrect as embryos do not retrace ancestral stages (recapitulation theory is outdated). Option C is wrong as embryos inside eggs can still show similarities. Option D is incorrect as humans do not have a two - chambered heart in early development (fish do, but this is a specific example, not the general principle for determining evolutionary relationships via embryonic development).

Answer:

B. Embryos of more closely related organisms show greater similarities in development.