At constant temperature, the rate of transpiration will be higher at

Options

A. Sea level
B. 1 km below sea level
C. 1 km above sea leval
D. 1.5 km above sea level

Explanation

To solve the question regarding the rate of transpiration at different altitudes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Transpiration**: Transpiration is the process by which plants lose water in the form of vapor through small openings called stomata. This process is influenced by several environmental factors, including atmospheric pressure.

2. **Identify the Factors Affecting Transpiration**: One of the key factors affecting the rate of transpiration is atmospheric pressure. Generally, lower atmospheric pressure leads to a higher rate of transpiration.

3. **Analyze the Options**: The question provides four options regarding different altitudes:
- Sea level
- 1 kilometer below sea level
- 1 kilometer above sea level
- 1.5 kilometers above sea level

4. **Relate Altitude to Atmospheric Pressure**: At sea level, atmospheric pressure is higher compared to higher altitudes. As we go above sea level, the atmospheric pressure decreases. Therefore, the rate of transpiration will increase with altitude due to lower pressure.

5. **Determine the Highest Altitude**: Among the given options, 1.5 kilometers above sea level represents the highest altitude. Since transpiration is higher at higher altitudes due to lower atmospheric pressure, we can conclude that the rate of transpiration will be highest at this altitude.

6. **Select the Correct Answer**: Based on the analysis, the correct answer is **1.5 kilometers above sea level**.

### Final Answer:
The rate of transpiration will be higher at **1.5 kilometers above sea level**.

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