Question

the wing of a bird and the leg of a horse are very different looking structures. although they look different, bird wings and horse legs are very similar the limb. which term is used by scientists to describe structures that look different on the outside but are actually similar in construction and develop a common descent b analogous structures c vestigial structures d homologous structures

Explanation:

To solve this, we analyze each option:

• Option A: "Common descent" refers to organisms sharing a common ancestor, not directly about structure similarity, so A is incorrect.
• Option B: "Analogous structures" have similar functions but different origins/construction (e.g., bird wing and insect wing), so B is incorrect.
• Option C: "Vestigial structures" are remnants with reduced function (e.g., human appendix), not matching the description, so C is incorrect.
• Option D: "Homologous structures" are structures that look different externally but have similar underlying construction and development (due to common ancestry), which matches bird wings and horse legs.

Answer:

D