Spraying kerosene on stagnant water shall kill Anopheles due to

Options

A. Prevention of spiracle to come in contact with air
B. Entry into and blocking of respiratory tract
C. Diffusion into body
D. Burning of body wall.

Answer

**Step-by-Step Solution:**

1. **Understanding the Problem**: The question asks why spraying kerosene on stagnant water kills Anopheles mosquitoes. Anopheles mosquitoes are known vectors for malaria and breed in stagnant water.

2. **Identifying the Mechanism**: Kerosene is a hydrocarbon that creates a film on the surface of the water. This film can affect the breathing mechanisms of the mosquitoes.

3. **Respiratory System of Anopheles**: Anopheles mosquitoes breathe through structures called siphons, which are located on their bodies. These siphons allow them to take in air while they are on the water's surface.

4. **Effect of Kerosene**: When kerosene is sprayed on stagnant water, it forms a layer on the surface. This layer acts as a mechanical barrier, preventing the mosquitoes from accessing the air they need to breathe.

5. **Suffocation Mechanism**: The kerosene can enter the breathing siphons of the mosquitoes, blocking their respiratory tract. This blockage leads to suffocation, as the mosquitoes cannot obtain the oxygen they need.

6. **Conclusion**: Therefore, the correct answer to the question is that spraying kerosene kills Anopheles mosquitoes due to "entry into and blocking of respiratory tract."

**Final Answer**: Entry into and blocking of respiratory tract.

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