Kidneys are excretory organs in

Options

A. All chordates
B. Mammals only
C. Mammals and amphibians only
D. Mammals reptiles and amphibians only

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the excretory organs in various groups of animals, specifically focusing on kidneys.

2. **Identifying the Options**: The options provided are:
- A) All caudates
- B) Mammals only
- C) Mammals and amphibians only
- D) Mammals, reptiles, and amphibians only

3. **Analyzing the Options**:
- **A) All caudates**: Caudates (or Urodela) include all animals with a backbone that have a tail at some stage of their life cycle, which includes amphibians and some other groups.
- **B) Mammals only**: This option is too restrictive as it excludes other vertebrates that also have kidneys.
- **C) Mammals and amphibians only**: This option also excludes reptiles and other groups that possess kidneys.
- **D) Mammals, reptiles, and amphibians only**: This option includes a broader range of vertebrates but still excludes fish and other caudates.

4. **Correct Answer**: The correct answer is **A) All caudates**. All caudates have kidneys as excretory organs, which are essential for urine formation and excretion.

5. **Conclusion**: The kidneys serve as excretory organs in all caudates, which include mammals, amphibians, and reptiles, among others.

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