Question

In studying humans, whales, and horses, which of the following set of similarities would be evidence for the most recent common ancestor?
they all have similar bones in their limbs, they are all mammals, they all have hair, they all have internal skeletons

Answer 1

The set of similarities that would provide the most evidence for a recent common ancestor among humans, whales, and horses is: **they all have similar bones in their limbs.**

This similarity indicates that despite differences in size and function of the limbs due to adaptation to different environments (terrestrial and aquatic), these species share a common structural framework, reflecting their evolutionary relationship. The similarity of limb bones is a classic example of homologous structures, which arise from a common ancestor.

The other options, while also indicative of shared ancestry (being mammals, having hair, and having internal skeletons), are more general characteristics that do not specifically point to the recent common ancestor of these three groups as clearly as the similarity in limb bones does.