Question

what structure has become useless through evolution but still exists, typically in a much reduced form?
a homologous
b analagous
c vestigial

Explanation:

To solve this, we analyze each option:

• Option a (Homologous): Homologous structures are similar due to common ancestry but may have different functions. They are not useless, so this is incorrect.
• Option b (Analagous): Analogous structures have similar functions but different evolutionary origins. They are not reduced or useless remnants, so this is incorrect.
• Option c (Vestigial): Vestigial structures are those that have lost their original function through evolution but still exist in a reduced form (e.g., human appendix, tailbone). This matches the description.

Answer:

c. Vestigial