Give scientific reasons for the following statements:
Contraceptive pills are helpful to prevent pregnancy.

Explanation

Pills used contraception form contraceptive chemical method.
`rarr` The female uses oral contraceptive pills.
`rarr` The oral pills contain a combination of hormones (progesterone) which stop the release of eggs and fertilisation cannot occur.
`rarr` By using, such pills fertilisation can be prevented.
Hence, contraceptive pills are helpful to prevent pregnancy.