Identify the incorrect statements

Options

A. Opsin is type of protein
B. Retinal is an aldehyde of vitamin -A
C. Light induces association of retinal and opsin which leads to vision
D. Both (2) and (3)

Answer

To identify the incorrect statements from the provided options, follow these steps:

### Step-by-Step Solution:

1. **Understand the Components**: Recognize that the question involves understanding the role of opsin and retinal in the mechanism of vision. Opsin is a type of protein, and retinal is an aldehyde derived from vitamin A.

2. **Analyze Each Statement**:
- **Statement 1**: "Opsin is a type of protein."
- This statement is correct. Opsin is indeed a protein found in photoreceptor cells.
- **Statement 2**: "Retinal is an aldehyde of vitamin A."
- This statement is also correct. Retinal is a derivative of vitamin A and is crucial for vision.
- **Statement 3**: "Light induces association of retinal and opsin which leads to vision."
- This statement is incorrect. Light actually induces the dissociation of retinal from opsin, not association.
- **Statement 4**: "Both second and third."
- This statement is ambiguous but implies that both the second and third statements are incorrect. However, since the second statement is correct, this statement cannot be true.

3. **Identify the Incorrect Statement**:
- The third statement is incorrect because it misrepresents the action of light on retinal and opsin. Light causes retinal to dissociate from opsin, leading to changes that initiate the visual process.

4. **Conclusion**: The incorrect statement is the third one: "Light induces association of retinal and opsin which leads to vision."

### Final Answer:
The incorrect statement is: **"Light induces association of retinal and opsin which leads to vision."**