Researchers have found fossils of Eocene horse species in Colorado. Deeper deposits contain smaller species, and more recent deposits contain larger species. How does this observation support the theory of evolution?

A) It proves that environments have changed over time.
B) It suggests that species are unchanging and of recent origin.
C) It does not support the theory of evolution.
D) It shows that all species are related to each other.
E) It provides evidence that species change over time.