What two kingdoms existed until 1937

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic

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.

Is this mrna or rna need need the answer in a hurry