Potometers are made on the principle that

Options

A. The amout of water transpired is approximately equal to amount of water absorbed
B. The amount of water transpired is more then the amount of water absorbed
C. The amount of water transpried is less then the amount of water absorbed
D. Humidity causes reduction in transpiration.

Answer

### Step-by-Step Solution:

1. **Understanding Potometers**: A potometer is a device used to measure the rate of water uptake by a plant, which is closely related to the rate of transpiration. Transpiration is the process where water is lost from the plant, primarily through small openings called stomata.

2. **Principle of Measurement**: The potometer operates on the principle that the amount of water transpired by the plant is approximately equal to the amount of water absorbed by the roots. This is because as the plant loses water through transpiration, it must take in an equivalent amount of water to maintain its physiological processes.

3. **Options Analysis**:
- **Option A**: The amount of water transpired is approximately equal to the amount of water absorbed. This aligns with the principle of potometers.
- **Option B**: The amount of water transpired is more than the amount of water absorbed. This is incorrect as it would imply a net loss of water.
- **Option C**: The amount of water transpired is less than the amount of water absorbed. This is also incorrect as it would not account for the water lost through transpiration.
- **Option D**: Humidity causes a reduction in transpiration. While humidity does affect transpiration rates, it does not relate to the fundamental principle of how potometers function.

4. **Conclusion**: Based on the understanding of how potometers work and the analysis of the options, the correct answer is **Option A**: The amount of water transpired is approximately equal to the amount of water absorbed.