The basic functional unit of human kidney is

Options

A. nephron
B. pyramid
C. nephridia
D. Henle's loop

Explanation

**Step-by-Step Solution:**

1. **Identify the Basic Functional Unit**: The question asks for the basic functional unit of the human kidney.

2. **Recall the Structure of the Kidney**: The human kidney is composed of various structures, but the primary functional unit responsible for filtering blood and forming urine is crucial to identify.

3. **Define Nephron**: The nephron is the basic functional unit of the kidney. Each kidney contains approximately one million nephrons.

4. **Understand the Components of a Nephron**: A nephron consists of several parts:
- **Bowman's Capsule**: This is the initial part of the nephron where filtration of blood occurs.
- **Proximal Convoluted Tubule (PCT)**: This segment reabsorbs nutrients, water, and ions from the filtrate.
- **Loop of Henle**: This part is responsible for concentrating urine and maintaining the body's water balance.
- **Distal Convoluted Tubule (DCT)**: This section further adjusts the composition of urine through secretion and reabsorption.

5. **Differentiate from Other Structures**:
- **Pyramids**: These are structures within the kidney but not functional units.
- **Nephridia**: These are excretory structures found in earthworms, not in humans.
- **Henle's Loop**: While it is part of the nephron, it is not the entire functional unit.

6. **Conclusion**: Based on the above points, the basic functional unit of the human kidney is the nephron.

**Final Answer**: The basic functional unit of the human kidney is the nephron.

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