According to this dichotomous key, any catfish must have a double dorsal fin, a small fin on the back near the tail, and barbs near the mouth. a single dorsal fin, no small fin on the back near the tail, and barbs near the mouth. a double dorsal fin, a small fin on the back near the tail, and no barbs near the mouth. a single dorsal fin, a small fin on the back near the tail, and barbs near the mouth.

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.