Final answer:
The correct size of both a fertilized mouse egg and human egg is approximately 100 micrometers in diameter, which facilitates fertilization and early development processes.
Step-by-step explanation:
The fertilized mouse egg and human egg are both approximately 100 micrometers in diameter. This size allows for the necessary biological processes to occur, such as fertilization and implantation. A mouse egg, similar to a human egg, is a large cell compared to other cells in the body, for example, a human red blood cell is only about eight micrometers in diameter.
The process of fertilization involves the union of a sperm and an egg to form a zygote. The sperm cell is much smaller with a tail for movement, while the egg is a larger cell, which serves as the environment for initial development. After the sperm penetrates the egg, a series of reactions occur to ensure that only one sperm fertilizes the egg, as described by Ernest Everett Just. This includes a fast block known as a "wave of negativity," changing the membrane potential, as well as a slow block which alters the egg's membrane structure.
Understanding the size of these vital reproductive cells provides insight into the microscopic world of conception and early embryonic development.