Assertion . No secondary growth takes place in monocots. Reason. Secondary growth is not related to cambium.

Options

A. both are true with reason being correct explanation.
B. both true but reason is not correct explanation.
C. assertion true but reason is wrong.
D. both are wrong

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that "No secondary growth takes place in monocots."
- **Explanation**: Monocots, such as grasses and lilies, lack secondary growth because they do not have lateral meristems (cambium) which are responsible for this type of growth.

2. **Understanding the Reason**: The reason given is "Secondary growth is not related to cambium."
- **Explanation**: This statement is incorrect. Secondary growth is indeed related to cambium, which is a type of lateral meristem that contributes to the formation of secondary vascular tissues (xylem and phloem) and protective tissues (cork).

3. **Evaluating the Truth of the Statements**:
- The assertion is true: Monocots do not undergo secondary growth due to the absence of cambium.
- The reason is false: Secondary growth is directly related to the presence of cambium.

4. **Conclusion**: Since the assertion is true and the reason is false, the correct answer to the question is that the assertion is correct while the reason is incorrect.

### Final Answer:
- The assertion is true, and the reason is false. Therefore, the correct option is option number three.