In What Way Does the Theory of Descent with Modification

In what way does the theory of descent with modification differ from the theory of evolution by natural selection?

A) Organisms can evolve even if natural selection is not responsible for the changes that occur.
B) Descent with modification applies only to large animals and plants and not to smaller organisms, like bacteria and protozoans.
C) The theory of descent with modification is designed to explain why organisms have evolved adaptations, whereas natural selection explains why organisms can persist unchanged over long periods of evolutionary time.
D) Descent with modification provides an account of the evolutionary events that took place as a modern species evolved from ancestral ones; natural selection theory provides a means for why some changes spread through a species while others did not.