(c) : The sperms in the female’s genital tract are made capable of fertilising the egg by secretions of the female genital tract. These secretions remove coat­ ing substances deposited on the surface of the sperms particularly those on the acrosome. Thus, the recep­ tor sites on the acrosome are exposed and sperm be­ comes active to penetrate the egg. This phenomenon of sperm activation in mammals is known as capaci­ tation.