Assertion :- Inner most layer of microsporangium or pollen sac, tapetum is of physiological significance.
Reason :- All kind of nutrition of developing pollen grains go through tapetum.

Options

A. A
B. B
C. C
D. D

Answer

To solve the assertion and reason question regarding the physiological significance of the tapetum in the microsporangium (pollen sac), we can break it down into the following steps:

### Step 1: Understand the Assertion
The assertion states that the innermost layer of the microsporangium, known as the tapetum, is of physiological significance.

**Explanation:** The tapetum is indeed the innermost layer of the pollen sac and plays a crucial role in the development of pollen grains. It provides essential nutrients and support for the developing microspores.

### Step 2: Analyze the Reason
The reason given is that all kinds of nutrition for developing pollen grains come through the tapetum.

**Explanation:** The tapetum consists of large, multinucleated cells that are responsible for supplying nutrients and enzymes necessary for the development of pollen grains. This statement is accurate as the tapetum directly influences the nourishment of the pollen grains.

### Step 3: Determine the Relationship Between Assertion and Reason
Now, we need to evaluate whether the reason correctly explains the assertion.

**Explanation:** Since the tapetum provides nutrition to the pollen grains and is indeed of physiological significance, the reason does provide a correct explanation for the assertion.

### Step 4: Conclusion
Based on the analysis, both the assertion and reason are true, and the reason correctly explains the assertion. Therefore, the correct answer to the question is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Answer
The correct answer is **Option A**: Both assertion and reason are true, and the reason is the correct explanation of the assertion.

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