Which of the following animals is not a pair of poikilotherms?

Options

A. Torpedo, Trygon
B. Trygon, panthera
C. Pristis, carcharodon
D. Scoliodon, Trygon

Answer

To determine which of the following animals is not a pair of poikilotherms, we need to analyze each option based on their classification as either poikilothermic (cold-blooded) or homeothermic (warm-blooded).

1. **Understanding Poikilotherms and Homeotherms**:
- Poikilotherms are animals whose body temperature varies with the ambient temperature. Examples include fishes, amphibians, and reptiles.
- Homeotherms maintain a constant body temperature regardless of the environment. This group includes birds and mammals.

2. **Analyzing the Options**:
- **Option A: Torpedo and Trigon**:
- Torpedo (electric ray) and Trigon (poison ray) are both types of fish. Therefore, both are poikilothermic.
- **Option B: Trigon and Panthera**:
- Trigon (poison ray) is a fish (poikilothermic), while Panthera (genus that includes lions and tigers) is a mammal (homeothermic). This option contains one poikilotherm and one homeotherm.
- **Option C: Carcharodon and Pristis**:
- Carcharodon (great white shark) and Pristis (sawfish) are both cartilaginous fishes. Thus, both are poikilothermic.
- **Option D: Scoliodon and Trigon**:
- Scoliodon (dogfish shark) and Trigon (poison ray) are both fishes, making them both poikilothermic.

3. **Conclusion**:
- The only option that contains an animal that is not a poikilotherm is **Option B: Trigon and Panthera**. Panthera is a warm-blooded mammal, while Trigon is a cold-blooded fish.

**Final Answer**: Option B (Trigon and Panthera) is the correct answer as it includes one poikilotherm and one homeotherm.

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