An egg is an organic vessel designed to nurture and protect a developing embryo. Found in birds, reptiles, amphibians, and fish, eggs vary in size, shape, and composition. The most commonly consumed eggs come from poultry, particularly chickens. Structurally, an egg consists of a protective shell, egg white (albumen), and yolk, each serving a unique biological function. Eggs are a rich source of protein and essential nutrients, making them a staple in diets worldwide.