Final answer:
Hormonal contraception is the primary chemical control method of birth control. It involves the administration of hormones to prevent ovulation and interfere with the fertilization and implantation of eggs. Hormonal contraception methods, such as birth control pills, injections, and skin patches, are effective in preventing pregnancy.
Step-by-step explanation:
The primary chemical control method of birth control is hormonal contraception. Hormonal methods involve the administration of hormones, such as estrogen and progesterone, to prevent ovulation. These hormones can be taken orally in birth control pills or received through other methods like injections or skin patches. The hormones in hormonal contraception prevent the release of eggs from the ovaries and also cause changes in the uterus and cervical mucus to prevent sperm from joining the egg.