Question

question 3(multiple choice worth 3 points)
(05.01 mc)
the observation that the front limbs of birds and reptiles have similar homologous structures supports which of the following?
birds and reptiles use these structures for the same motion
birds and reptiles developed in parallel without relation.
birds and reptiles evolved from a common ancestor.
birds and reptiles were influenced by the same environmental factors

Explanation:

Homologous structures are anatomical features in different organisms that share a common underlying structure due to inheritance from a common ancestor. Just because birds and reptiles have homologous front - limb structures does not mean they use them for the same motion (birds use wings for flying, many reptiles use front limbs for walking). If they developed in parallel without relation (convergent evolution), the structures would be analogous, not homologous. Environmental factors influencing them the same would also lead to analogous structures in most cases. But homologous structures strongly suggest a common ancestor.

Answer:

Birds and reptiles evolved from a common ancestor.