Assertion : Psilotum is living fossil
Reason: Equisetum in heterosporous ptridophyte.

Options

A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but Ris not correct explanation of A
C. A is true but R is false
D. A and R are false

Answer

To solve the assertion and reason question, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
**Assertion:** Psilotum is a living fossil.

- **Explanation:** Psilotum is a genus of plants that is considered a "living fossil" because it has existed in a form that is very similar to its ancient ancestors. It represents a lineage that has survived through geological time, while many related species have gone extinct. Therefore, this assertion is true.

### Step 2: Analyze the Reason
**Reason:** Equisetum is a heterosporous pteridophyte.

- **Explanation:** Equisetum, commonly known as horsetail, is actually a homosporous pteridophyte, meaning it produces only one type of spore. Heterosporous plants produce two different types of spores: microspores and megaspores. Since Equisetum does not fit this definition, the reason provided is false.

### Step 3: Conclusion
- **Assertion:** True
- **Reason:** False

### Step 4: Identify the Correct Option
Given the analysis:
- The assertion is true, but the reason is false. This corresponds to the option that states "Assertion is true, but Reason is false."

### Final Answer
The correct answer is **Option 3**: Assertion is true, but Reason is false.

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