The functional adult kidney of human being is

Options

A. archinephros
B. pronephros
C. mesonephros
D. Metanephros

Answer

**Step-by-Step Solution:**

1. **Understanding Kidney Development Stages**: The development of kidneys in humans occurs in several stages. It's important to recognize these stages to identify which one is functional in adults.

2. **Identifying the Stages**:
- **Archaeonephros**: This is the earliest stage of kidney development, found in certain aquatic organisms like the larva of Hackfish. It is not present in humans.
- **Pronephros**: This is the first stage of kidney development in embryos. It is temporary and not functional in adults.
- **Mesonephros**: This is the second stage of kidney development, also present in embryos. It serves a temporary function but is not the adult kidney.
- **Metanephros**: This is the final stage of kidney development and is the functional kidney in adult humans.

3. **Conclusion**: Based on the stages of kidney development, the functional adult kidney in humans is the Metanephros.

**Final Answer**: The functional adult kidney of a human being is Metanephros.

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