Which of the following is not an example of response to stimulus?

Options

A. Watering in mouth when we see delicious food items.
B. Closing of leaves of mimosa plant when touched.
C. Shutting our eyes when an object is suddenly thrown in our direction.
D. A chick hatching out of an egg.

Answer

To determine which of the following is not an example of a response to a stimulus, we will analyze each option provided.

### Step-by-Step Solution:

1. **Understand the concept of stimulus**: A stimulus is any change in the environment that can provoke a response in an organism. Responses to stimuli are actions or changes in behavior that occur as a result of the stimulus.

2. **Evaluate the first option**:
- **Watering in mouth when we see a delicious food item**: This is a response to the visual stimulus of seeing food. The sight of food triggers salivation, which is a clear response to a stimulus.

3. **Evaluate the second option**:
- **Closing of leaves of the mimosa plant when touched**: This is a response to the tactile stimulus of touch. The plant reacts by closing its leaves, which is a direct response to the stimulus.

4. **Evaluate the third option**:
- **Shutting our eyes when an object is suddenly shown in our direction**: This is a protective response to a visual stimulus. The sudden appearance of an object triggers the reflex to close the eyes, which is a response to the stimulus.

5. **Evaluate the fourth option**:
- **A chick hatching out from an egg**: This event is a part of the reproductive process. It does not involve a response to an external stimulus in the same way the other examples do. The hatching is a natural process of development rather than a reaction to a stimulus.

6. **Conclusion**: The option that is not an example of a response to a stimulus is **the chick hatching out from an egg**.

### Final Answer:
The chick hatching out from an egg is not an example of a response to a stimulus.

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