Most eggs that are eaten by humans, including bird eggs and turtle eggs, have a protective, oval eggshell, the albumen (egg white), the vitellus (egg yolk), and various thin membranes, that are layers like skin. Every part of the egg is edible, although the eggshell is usually thrown away. Eggs are a good source of protein and choline. It also a source of some micro nutrients such as vitamin A, vitamin D, vitamin E, vitamin K, etc.