Tulip flowers shows

Options

A. Photonasty
B. Thermonasty
C. Thigmonasty
D. Hydronasty

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the type of movement exhibited by tulip flowers. The options provided are photonasty, thermonasty, thigmonasty, and hydronasty.

2. **Defining Nastic Movements**: Nastic movements are plant movements that occur in response to stimuli, but they are not dependent on the direction of the stimulus. They can be classified based on the type of stimulus.

3. **Analyzing the Options**:
- **Photonasty**: This refers to movements in response to light. For example, flowers that open or close based on light availability.
- **Thermonasty**: This refers to movements in response to temperature changes. For example, flowers that open in warm temperatures and close in cooler temperatures.
- **Thigmonasty**: This refers to movements in response to touch or mechanical stimulation. An example would be the closing of a Venus flytrap when it is touched.
- **Hydronasty**: This refers to movements in response to water availability.

4. **Identifying the Correct Response for Tulip Flowers**: Tulip flowers open and close in response to temperature changes. They tend to open when the temperature is high and close when the temperature is low. This indicates that their movement is a response to temperature, which is defined as thermonasty.

5. **Conclusion**: Based on the analysis, the correct answer is **thermonasty**.

### Final Answer:
**Thermonasty** (Option B) is the correct choice for the type of movement exhibited by tulip flowers.

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