The unity and diversity of organisms become apparent even at the cellular level. - Albert L. Lehninger

Perhaps the most remarkable property of living cells and organisms is their ability to reproduce themselves for countless generations with nearly perfect fidelity. This continuity of inherited traits implies constancy, over millions of years, in the structure of the molecules that contain the genetic information.

Organisms possess extraordinary attributes, properties that distinguish them from other collections of matter. What are these distinguishing features of living organisms?

The distinguishing characteristics of eukary­otes are the nucleus and a variety of membrane-enclosed organelles with specific functions.