Overpopulation is caused by

1. Analyze the question Overpopulation happens when the number of people in an area is too large for the available resources (food, jobs, housing, social amenities). The question asks which option is a cause of this.

2. Explain the concept Population grows when birth rates are high relative to death rates, and when immigration exceeds emigration. Overpopulation is usually driven by:

• High birth rates (large family sizes, early marriage)
• Falling death rates (better healthcare)
• Immigration
• Low literacy and low awareness of family planning

3. Solution: test each option

• A. Emigration: This means people leaving a country. It reduces population, so it cannot cause overpopulation.
• B. Disease: Disease raises the death rate and so reduces population growth. It is not a cause.
• C. Low literacy rates: Where education is limited, especially for girls and women, people tend to have more children. Awareness of family planning and contraception is also low. Birth rates stay high, and population grows faster than resources. This is a recognised cause.
• D. War and conflicts: These lead to deaths and displacement, which reduce population, so this is not a cause.

4. Answer The correct option is **C.

5. Exam tip Ask yourself: "Does this factor increase or decrease the population?" Emigration, disease and war all reduce population, so they can be eliminated quickly. Only the option that pushes birth rates up (low literacy) fits "overpopulation".