Aeroplanes usually fly in the stratosphere because

Options

A. of the presence of ozone layer
B. of the atmosphere being turbulent
C. of the decrease in temperature with altitude
D. of the absence of convection current

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks why aeroplanes usually fly in the stratosphere.

2. **Identifying Key Characteristics of the Stratosphere**: The stratosphere is a layer of the atmosphere that is located above the troposphere and below the mesosphere. It is characterized by a steady temperature increase with altitude.

3. **Absence of Convection Currents**: One of the main reasons aeroplanes fly in the stratosphere is the absence of convection currents. In the troposphere, where weather occurs, convection currents can cause turbulence, which is not ideal for flying.

4. **Temperature Increase with Altitude**: In the stratosphere, the temperature increases with altitude. This is due to the absorption of ultraviolet (UV) radiation by the ozone layer, which leads to a more stable atmosphere.

5. **Lack of Turbulence**: The stable conditions in the stratosphere mean that there is less turbulence compared to the lower layers of the atmosphere. This stability is crucial for safe and efficient flight.

6. **Conclusion**: Therefore, aeroplanes fly in the stratosphere primarily due to the absence of convection currents, the increase in temperature with altitude, and the lack of turbulence.

**Final Answer**: Aeroplanes usually fly in the stratosphere because of the absence of convection currents and the stable atmospheric conditions that allow for safer and more efficient flying.

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