Final answer:
The chalazae in an egg serve to anchor the yolk in the center of the egg white, providing stability and proper orientation for the developing embryo.
Step-by-step explanation:
The principal purpose of the chalazae in an egg is to hold the yolk in place within the egg white (albumen). The chalazae are two spiral bands of tissue that attach to opposite ends of the yolk and extend to the interior shell membrane. They act like stabilizers, allowing the yolk to remain suspended in the center of the egg and to turn on its axis so that the developing embryo can maintain its position relative to the endoderm, which is rich in nutrients essential for its development.
This is crucial because it ensures that the embryo, which develops on the surface of the yolk, stays surrounded by the nourishment it needs to grow. This also helps to protect the embryo by acting as a shock absorber during movement or transportation of the egg.