On touching, the leaves of Mimosa pudica droop down because of

Options

A. Seismonasty
B. Nyctinasty
C. Chemonasty
D. Thigmotropism.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks why the leaves of Mimosa pudica droop down upon being touched.

2. **Identifying Plant Movements**: There are different types of movements in plants, known as 'nastic movements', which are responses to stimuli. The options provided include:
- Cispanasty
- Nicety nasty
- Chemo nasty
- Thigmotropism

3. **Defining Cispanasty**: Cispanasty refers to the nastic movement of a plant in response to touch or vibration. This is the primary movement observed in Mimosa pudica when its leaves droop upon contact.

4. **Evaluating Other Options**:
- **Nicety Nasty**: This is not a recognized term in plant movements and is likely a misinterpretation or typo.
- **Chemo Nasty**: This refers to the response of plants to chemical stimuli, which does not apply to the drooping of Mimosa pudica leaves.
- **Thigmotropism**: This is a growth response to touch, but it is not the correct term for the rapid movement of leaves in response to touch.

5. **Conclusion**: The correct answer is Cispanasty, as the drooping of Mimosa pudica leaves is a rapid response to touch.

**Final Answer**: The leaves of Mimosa pudica droop down because of Cispanasty.

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