Contraceptive pills are very effective with lesser side-effects and are well accepted by the females. They work by

Options

A. Inhibiting ovulation
B. Inhibiting implantation
C. They alter the quality of cervical mucus to prevent/retard the entry of sperms.
D. All of these

Answer

**Step-by-Step Solution:**

1. **Understanding Contraceptive Pills**: Contraceptive pills, also known as oral contraceptives, are medications taken by females to prevent pregnancy. They are effective and have fewer side effects compared to other contraceptive methods.

2. **Mechanism of Action**: The primary mechanisms through which contraceptive pills work include:
- **Inhibiting Ovulation**: The pills prevent the release of an egg from the ovaries. This means that there is no egg available for sperm to fertilize, thereby preventing pregnancy.
- **Inhibiting Implantation**: In case fertilization does occur, the pills make the uterine lining unsuitable for the implantation of the fertilized egg (zygote). This further reduces the chances of pregnancy.
- **Altering Cervical Mucus**: The pills also change the quality of cervical mucus, making it thicker. This thick mucus acts as a barrier to sperm, preventing them from entering the uterus.

3. **Conclusion**: Given these mechanisms, contraceptive pills effectively prevent pregnancy through multiple pathways: by inhibiting ovulation, preventing implantation, and altering cervical mucus.

**Final Answer**: Contraceptive pills work by inhibiting ovulation, inhibiting implantation, and altering the quality of cervical mucus to prevent the entry of sperm.

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