Apattern of evolution that results when two unrelated species begin to appear similar because of environmental conditions is about the relationship between a dolphin and a shark).

it has one origin of replication, but it proceeds in two directions - d)

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands