Birth Control Pills

Birth control pills:

A) kills sperm cells by creating a hostile environment within the uterus.
B) facilitates the implantation of a fertilized egg into the lining of the uterus.
C) promote the fertilization of the egg by a sperm cell.
D) prevent ovulation from occurring by changing a woman's hormone levels.
E) obstruct the cervix and thus prevents sperm from entering the uterus.