Question

According to the diagram, these organisms evolved from a common ancestor. What evidence backs up this theory? All BUT ONE answer contributes to the explanation.

Responses
The four animals have different forelimbs, reflecting different lifestyles.
The four animals have different forelimbs, reflecting different lifestyles.
The different forelimbs share the same set of bones: humerus, radius, and ulna.
The different forelimbs share the same set of bones: humerus, radius, and ulna.
The organisms once lived in similar habitats and were under similar environmental pressures.
The organisms once lived in similar habitats and were under similar environmental pressures.
We would expect the forelimb bones to be the same bones seen in fossils of an extinct common ancestor.

Answer 1

"The organisms once lived in similar habitats and were under similar environmental pressures."

Reason: similar habitats/pressures would suggest convergent evolution (independent evolution of similar traits), not common ancestry. The other statements (shared bone set, modified forelimbs for different lifestyles, and expected fossil bones) are evidence of homology and a common ancestor.