Sprinking oil over ponds would control malaria because

Options

A. Fishes die
B. Water gets polluted
C. Larvae are asphyxiated
D. Mosquitoes are repelled.

Answer

**Step-by-Step Solution:**

1. **Understanding the Problem**: The question asks why sprinkling oil over ponds would help control malaria. Malaria is transmitted by mosquitoes, which breed in stagnant water.

2. **Role of Oil**: When oil is sprinkled over the surface of ponds, it creates a thin film that covers the water. This film can affect the organisms living in the water, particularly mosquito larvae.

3. **Effect on Mosquito Larvae**: The oil film prevents mosquito larvae from accessing the surface of the water to breathe. Mosquito larvae need to come to the surface to inhale oxygen. When they are unable to do so, they suffer from asphyxiation.

4. **Consequences of Larval Death**: If the larvae die due to suffocation, they cannot mature into adult mosquitoes. This leads to a decrease in the mosquito population, which is crucial for controlling malaria transmission.

5. **Clarifying Misconceptions**: It is important to note that while some might think that oil could pollute the water or harm fish, the type of oil used is usually chosen to minimize environmental impact. The primary effect is on the larvae, not on fish.

6. **Conclusion**: Therefore, the correct reason why sprinkling oil over ponds controls malaria is that it asphyxiates the mosquito larvae, preventing them from growing into adult mosquitoes.

**Final Answer**: Sprinkling oil over ponds would control malaria because it asphyxiates the mosquito larvae, preventing their development into adult mosquitoes.

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