Assertion. A pollen grain of angiosperm is considered as the male gametophyte .
Reason. All the nuclei of the pollen grain produce male gametes.

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that a pollen grain of angiosperms is considered a male gametophyte.
- In angiosperms (flowering plants), pollen grains are indeed the male gametophytes, which means they are the structures that carry the male gametes (sperm cells).

2. **Understanding the Reason:**
- The reason provided is that all the nuclei of the pollen grain produce male gametes.
- However, this statement is not entirely accurate. While pollen grains do produce male gametes, not all nuclei in the pollen grain are responsible for this.

3. **Structure of Pollen Grain:**
- A pollen grain consists of two main cells: the vegetative cell and the generative cell.
- The vegetative cell does not produce male gametes; it is responsible for the growth of the pollen tube.
- The generative cell divides to form two male gametes.

4. **Evaluating the Statements:**
- The assertion is true because pollen grains are indeed male gametophytes.
- The reason is false because not all nuclei in the pollen grain produce male gametes; only the generative cell does.

5. **Conclusion:**
- Therefore, the correct evaluation of the assertion and reason is that the assertion is true, but the reason is false.

**Final Answer:**
- The assertion is true, and the reason is false.

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