Kidneys of birds are

Options

A. pronephic
B. mesonephric
C. archinephaic
D. metanephric

Answer

### Step-by-Step Solution:

1. **Understanding the Types of Kidneys**:
- The first step is to understand the different types of kidneys present in vertebrates: Pronephric, Mesonephric, Archinephric, and Metanephric.

2. **Identifying the Kidney Type in Birds**:
- Among these types, we need to identify which one is characteristic of birds. It is known that birds possess metanephric kidneys.

3. **Function of Metanephric Kidneys**:
- Metanephric kidneys are the functional kidneys in adult birds, responsible for excretion.

4. **Embryonic Development**:
- During embryonic development, birds initially form mesonephric kidneys, which are later modified or lost as they develop into adult birds.

5. **Eliminating Incorrect Options**:
- Pronephric: This is the first stage of kidney development and is not found in adult birds.
- Mesonephric: This is the adult kidney in some other vertebrates but not in birds.
- Archinephric: This refers to the ancestral kidney type and is not applicable to birds.
- Metanephric: This is the correct type of kidney found in adult birds.

6. **Conclusion**:
- Based on the information and elimination of incorrect options, we conclude that the kidneys of birds are metanephric.

### Final Answer:
The kidneys of birds are **metanephric**.

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