List the differences between the hearts of vertebrates that live in water and the hearts of vertebrates that live on land. List the similarities.

All vertebrates have circulatory systems based on a common plan, and so vertebrate systems show much less variety than do those of invertebrates. Although it is impossible to trace the evolution of the circulatory system by using fossils (because blood vessels do not fossilize as do bones and teeth), it is possible to theorize on its evolution by studying different groups of vertebrates and their developing embryos. Many of the variations from the common plan are related to the different requirements of living in water and on land.

Explanation:

answer; the tunica intima also called tunica interna, consists of elastic fibers,connective tissue and smooth muscle cells;