Assertion (A): Perspiration helps to maintain our body temperature.
Reason (R):Perspiration expels nitrogenous wastes from our body.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion (A):** The assertion states that "Perspiration helps to maintain our body temperature." This is true because perspiration (sweating) is a physiological process that helps cool the body when it gets too hot. When sweat evaporates from the skin, it removes heat, thus lowering the body temperature.

2. **Understanding the Reason (R):** The reason given is "Perspiration expels nitrogenous wastes from our body." This statement is also true. While the primary function of perspiration is thermoregulation, it does also help in the excretion of certain waste products, including small amounts of nitrogenous wastes like urea.

3. **Analyzing the Relationship:** Now, we need to analyze whether the reason is a correct explanation of the assertion. Although both statements are true, the reason does not directly explain the assertion. The main purpose of perspiration is to regulate body temperature, while the expulsion of nitrogenous waste is a secondary function.

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