<span>Enzymes antibodies and clotting compounds are made of proteins, in which these proteins generally exist in different forms and a common example of it are the amino acids. To add up, these enzyme antibodies aids the immune system by serving as a catalytic antibody producing a hapten molecule.</span>
Darwin called the ability of an organism to survive and reproduce in its environment fitness.
Some organisms were fit to do all of these things, whereas others were not.
D. Predators
Predators keep populations of other species in check. This was pretty clearly demonstrated in Yellowstone National Park after the wolves were eradicated there. The deer populations increased to the point that the aspen trees nearly disappeared due to the saplings' being eaten by deer. Since the reintroduction of wolves to the park, the aspen trees have begun to flourish once again.
