Similarities in the bones of the human arm and a whale's flipper suggest what about these organisms?
a.) they have the same dna.
b.) they have nothing in common.
c.) they share a common ancestor.
d.) whales evolved from humans.

They share a common ancestor which is one of the ecological concepts of common descent

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.