What similarities in the development lead scientists to infer that opossums ,chickens, salamanders, and fish share a common ancestor?

If scientists are wrong about earth's age based on radioactive material and the decay rates are really much faster, how would nuclear power plants be affected?

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.

For an animal living a diplontic cycle, meiosis is limited to: producing gametes producing growth fertilization development of the zygote