In aerobic respiration, what is the direct source of energy that atp synthase uses to synthesize atp? a. an electron gradient b. an exergonic chemical reaction c. a water gradient d. a proton gradient

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.