Assertion:- In Ascomycetes and Basidiomycetes well distinct Dikaryophase present during sexual life.
Reason:- During sexual reproduction of Ascomycetes and Basidiomycetes plasmogamy is immediately followed by karyogamy.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

To solve the question, we need to analyze both the assertion and the reason provided:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that in Ascomycetes and Basidiomycetes, a well-distinct dikaryophase is present during their sexual life cycle.
- This is true because in these fungi, after the process of plasmogamy (fusion of cytoplasm), there is a phase where two distinct nuclei coexist in the same cell, known as the dikaryophase.

2. **Understanding the Reason**:
- The reason states that during sexual reproduction of Ascomycetes and Basidiomycetes, plasmogamy is immediately followed by karyogamy (fusion of nuclei).
- This statement is false. In fact, there is a delay between plasmogamy and karyogamy, during which the dikaryophase occurs.

3. **Evaluating the Relationship**:
- Since the assertion is true and the reason is false, we can conclude that the reason does not correctly explain the assertion.

4. **Choosing the Correct Option**:
- Based on the analysis, the correct answer is that the assertion is true and the reason is false.

### Final Answer:
The correct option is: **Assertion is true and Reason is false.**