When the grand canyon was forming, a population of squirrels were separated into two groups. the north side of the canyon is at a higher elevation and experiences more rainfall than the south side of the canyon. the two squirrel species you see here had a common ancestor, but over time, have evolved into two different species. how did natural selection lead to different species?

The embryos of a bird, a reptile, and a mammal are similar in appearance. how does comparing the physical appearance of embryos of different species support the theory of evolution? a. it shows that these organisms share a common ancestor. b. it provides evidence that these organisms eat the same foods. c. it shows that these organisms share the same habitat. d. it provides evidence that these organisms suffered a genetic mutation.