Assertion (A): Oral pills taken by females are an effective method of…

The correct answer is Option (1) → Both A and R are true, and R is the correct explanation of A.

Assertion (A): Oral pills taken by females are an effective method of preventing conception. — True. Oral pills contain small doses of progestogens or progestogen–estrogen combinations. They are taken daily for 21 days, and the book calls them very effective, with fewer side effects.

Reason (R): Pills inhibit ovulation and implantation as well as alter the quality of cervical mucus to prevent/retard the entry of sperms. — True. Pills inhibit ovulation and implantation, and they change the cervical mucus so that sperms cannot enter or are slowed down.

Why R explains A? A says that pills prevent conception. R gives how they do it: with no ovum released, no implantation and a barrier of thick cervical mucus against sperms, fertilisation and pregnancy cannot take place. This working is the reason the pills are effective. So both statements are correct, and R is the correct explanation of A.

NCERT Extract:
Population Stabilisation and Birth Control – “… Oral administration of small doses of either progestogens or progestogen–estrogen combinations is another contraceptive method used by the females. They are used in the form of tablets and hence are popularly called the pills. Pills have to be taken daily for a period of 21 days starting preferably within the first five days of menstrual cycle. After a gap of 7 days (during which menstruation occurs) it has to be repeated in the same pattern till the female desires to prevent conception. They inhibit ovulation and implantation as well as alter the quality of cervical mucus to prevent/retard entry of sperms. Pills are very effective with lesser side effects and are well accepted by the females.”