In the human body, kidney is the part of which system?

Options

A. Excretory
B. Digestive
C. Respiratory
D. Nervous

Explanation

**Step-by-Step Solution:**

1. **Identify the Organ in Question**: The question asks about the kidney, which is a vital organ in the human body.

2. **Understand the Function of the Kidney**: The primary function of the kidney is to filter blood, remove waste products, and regulate fluid balance in the body.

3. **Recognize the Structural Unit**: The kidney contains nephrons, which are the structural and functional units responsible for the filtration process.

4. **Determine the System Involved**: The kidney plays a crucial role in the excretion of waste. The waste filtered from the blood is converted into urine, which is expelled from the body.

5. **Conclude the System**: Since the kidney is responsible for filtering waste and producing urine, it is part of the excretory system.

**Final Answer**: The kidney is part of the excretory system.

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