THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -It takes just one sperm to fertilize a woman’s egg. Keep in mind, though, for each sperm that reaches the egg, there are millions that don’t. On average, each time men ejaculate they release nearly 100 million sperm.

Detailed explanation-2: -Two mechanisms can operate to ensure that only one sperm fertilizes the egg. In many cases, a rapid depolarization of the egg plasma membrane, which is caused by the fusion of the first sperm, prevents further sperm from fusing and thereby acts as a fast primary block to polyspermy.