An egg is a round or oval object produced by female animals, particularly birds, reptiles, and some mammals. It contains a protective shell, which can be hard or soft, and is filled with a nutrient-rich substance called egg white and yolk. Eggs are a common food source for humans and are used in various dishes, such as omelets and cakes. The most commonly consumed eggs come from chickens, but other birds like ducks and quails also lay edible eggs. Eggs are a good source of protein, vitamins, and minerals, making them a nutritious addition to many diets.