Question

what did reptiles develop that was different from their ancestors?
hair and fur
feathers
live birth of offspring
amniotic eggs

Explanation:

To solve this, we analyze each option:

• Hair and fur are characteristics of mammals, not reptiles.
• Feathers are developed by birds (a type of reptile descendant, but not a defining reptilian development from ancestors).
• Most reptiles lay eggs, and live birth is not a key development distinguishing them from ancestors (amphibians, their likely ancestors, have different reproductive strategies, and reptiles' main reproductive innovation is amniotic eggs, not live birth as a primary difference).
• Reptiles developed amniotic eggs, which have a membrane (amnion) that protects the embryo, allowing them to reproduce on land, unlike their amphibian - like ancestors which needed water for reproduction.

Answer:

D. amniotic eggs (assuming the options are labeled A to D with D being "amniotic eggs", following the order: A. hair and fur, B. feathers, C. live birth of offspring, D. amniotic eggs)