Instrument that can be used to demonstrate pull due to vaporisation of water is

Options

A. Potometer
B. Atmometer
C. Auxanometer
D. Anemometer

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for an instrument that demonstrates the pull due to the vaporization of water in plants. This phenomenon is related to transpiration, where water vapor is lost from the plant, creating a negative pressure that pulls more water upward from the roots.

2. **Identifying the Options**: The options provided are:
- Potometer
- Ethmometer
- Oxanometer
- Anemometer

3. **Analyzing Each Option**:
- **Potometer**: This instrument measures the rate of water uptake by a plant but does not specifically demonstrate the pull due to vaporization.
- **Ethmometer (or Evaporimeter)**: This device measures the rate of evaporation of water from a wet surface to the atmosphere. It is directly related to the concept of vaporization and the resulting pull in plants.
- **Oxanometer**: This instrument measures the growth rate of plants, which is not directly related to vaporization.
- **Anemometer**: This device measures wind speed and is not related to water vaporization in plants.

4. **Conclusion**: Among the options, the **Ethmometer** is the correct instrument that can demonstrate the pull due to the vaporization of water.

### Final Answer:
The instrument that can be used to demonstrate the pull due to vaporization of water is the **Ethmometer**.

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