MICROANATOMY

Detailed explanation-1: -Once fertilized, the egg is called a zygote. Fertilization is not complete, however, until the two haploid nuclei (called pronuclei ) have come together and combined their chromosomes into a single diploid nucleus.

Detailed explanation-2: -Only one sperm can fertilize an egg because there is a process called cortical reaction that prevents polyspermy. Many sperms can attach to the membrane of the egg, but due to this reaction, only one fuses with the membrane and fertilize the egg.

Detailed explanation-3: -The mixing of the sperm and egg is called insemination. Eggs and sperm are then stored in an environmentally controlled chamber. The sperm most often enters (fertilizes) an egg a few hours after insemination.