In studying humans, whales, and horses, which of the following set of similarities would be evidence for the most recent common ancestor?
a
they all have hair.
b
they all have internal skeletons.
c
they are all mammals.
d
they all have similar bones in their limbs.
The correct answer is (c) they are all mammals. Mammals are a class of animals that share common characteristics including hair/fur, mammary glands, three middle ear bones, and a neocortex region of their brain. Therefore, the fact that humans, whales, and horses are all mammals provides the strongest evidence for a most recent common ancestor.
The set of similarities that would be evidence for the most recent common ancestor among humans, whales, and horses is:
C) They are all mammals.
This is because mammals share a common ancestor and have many characteristics in common, such as giving birth to live young, having mammary glands to produce milk, and having hair or fur.