Why Would the DNA of Cats and Dogs Be Much

Question

Why would the DNA of cats and dogs be much more similar than the DNA of cats and hamsters?
A) Cats and dogs have lived together with humans for a longer time and have become more similar.
B) Cats and dogs have a more recent common ancestor than the common ancestor of cats and hamsters.
C) The ancestors of cats and the ancestors of dogs evolved in similar environments.
D) Cats and dogs have fewer offspring during their lifetime than hamsters, so their DNA changes less rapidly.

Accepted Answer

DNA similarity between species is based on their evolutionary relatedness. The more recent the common ancestor, the more similar the DNA will be. Therefore, cats and dogs, which are both mammals and have a more recent common ancestor than cats and hamsters (which are from different orders of mammals), will have more similar DNA. The other choices are not supported by evidence or are not directly related to DNA similarity.