Assertion (A): Osmoregulation is one of the functions of kidney.
Reason (R): Nutrients are transported to the bloodstream from the renal tubule by the process of osmosis.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion (A)**: The assertion states that "Osmoregulation is one of the functions of the kidney." This is true because the kidneys play a crucial role in regulating the water balance and electrolyte levels in the body, which is known as osmoregulation.

2. **Understanding the Reason (R)**: The reason states that "Nutrients are transported to the bloodstream from the renal tubule by the process of osmosis." This statement is misleading. While the kidneys do reabsorb nutrients, the process primarily involves active transport rather than osmosis. Osmosis specifically refers to the movement of water, not nutrients.

3. **Evaluating the Relationship**: Since the assertion is true but the reason is not a correct explanation of the assertion, we need to analyze the options provided:
- Option 1 states that both assertion and reason are true and the reason is a correct explanation of the assertion. This is incorrect because the reason is not a correct explanation.
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