Eggs are the vessel for offspring for various species. Chicken eggs in particular are widely used for human nutrition.
The Egg is divided into a yellow-orange nutrient sac known as the 'Yolk' and the proteinaceous albumin known as the 'White'. The Yolk tends to be the source of most dietary fat and is designed to feed the fetus (if it were present), and the whites the source of most dietary protein and are designed to both supply the yolk with nutrition and to protect the yolk either physically or enzymatically.
Some nutrients or non-nutritive components are placed ubiquitously across the egg, while others are isolated to either the yolk or the white.