Assertion : Heterospory and retention of female gametophyte are responsible for origin of seed habit in Selaginella
Reason : Psilotum is a living fossil

Options

A. (a) If both assertion and reason are true and reason is the correct explanation of assertion.
B. (b) If both assertion and reason are true but reason is not the correct explanation of assertion.
C. (c) If assertion is true but reason is false.
D. (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 1: Understand the Assertion
The assertion states that "Heterospory and retention of female gametophyte are responsible for the origin of seed habit in Selaginella."

- **Heterospory** refers to the production of two distinct types of spores: microspores (male) and megaspores (female).
- In Selaginella, the female gametophyte is retained within the megasporangium, which is a key feature in the evolution of seed plants.

**Conclusion**: The assertion is **true** because heterospory and the retention of the female gametophyte are indeed significant factors in the development of seed habit in Selaginella.

### Step 2: Understand the Reason
The reason states that "Psilotum is a living fossil."

- **Psilotum** (often referred to as Psilotum nudum) is a genus of plants that is considered a living fossil because it resembles ancient plants from the Devonian period.
- It is important to note that while Psilotum is a living fossil, this fact does not have a direct connection to the assertion about Selaginella's seed habit.

**Conclusion**: The reason is also **true**, but it does not explain the assertion regarding Selaginella.

### Step 3: Determine the Relationship
Now we need to evaluate the relationship between the assertion and the reason:

- Both the assertion and the reason are true.
- However, the reason does not provide an explanation for the assertion.

### Final Conclusion
Based on the analysis:
- The assertion is true.
- The reason is true.
- The reason does not explain the assertion.

Thus, the correct answer is that both statements are true, but the reason does not explain the assertion.