Answer: Correct options B, D and E.
Explanation:
In the cladogram, we can see that in the first branch we have a division, one branch goes to fish and the other goes to a division (a division means a common ancestor)
Then the fish are the most primitive (being directly related to the first ancestor)., E is true.
We also can see that between fish and birds we have 3 separations (the ancestor in common is 3 "generations" behind), and between frog and birds we have two separations (the common ancestor is 2 "generations" behind), so frogs are more closely related to birds than fish.
So D is also true.
We also can see that the only pair that has only one ancestor in common are birds and reptiles, so the ones that are most closely related are birds and reptiles. B is also true,
Which form of natural selection on polygenic traits results in the creation of two distinct phenotypes? The answer is, <u><em>B. Disruptive selection</em></u>
Answer: They aren't classified as birds because monotremes are mammals, unlike birds. They are referred to as mammals because they have mammary glands responsible for manufacturing and producing milk. Birds cannot do this.
