Assuming that an animal generates heat at a rate proportional to its volume and can radiate heat at a rate proportional to its body surface area, which of the following would be best at maintaining its body temperature in a cold climate ?

Options

A. Mouse
B. Rabbit
C. Bear
D. Fox

Explanation

To determine which animal would be best at maintaining its body temperature in a cold climate, we need to analyze the relationship between an animal's size, its heat generation, and heat loss.

### Step-by-Step Solution:

1. **Understanding Heat Generation and Loss**:
- An animal generates heat at a rate proportional to its **volume**.
- It radiates heat at a rate proportional to its **surface area**.

2. **Volume and Surface Area Relationship**:
- As an animal's size increases, its volume increases faster than its surface area.
- This means that larger animals have a lower surface area to volume ratio compared to smaller animals.

3. **Implications of Surface Area to Volume Ratio**:
- A lower surface area to volume ratio means that larger animals lose heat more slowly.
- Conversely, smaller animals have a higher surface area to volume ratio, leading to faster heat loss.

4. **Adaptations in Cold Climates**:
- In cold climates, animals need to retain heat to survive.
- Larger animals are better adapted to cold environments because they generate more heat (due to larger volume) and lose less heat (due to smaller surface area relative to volume).

5. **Evaluating the Given Options**:
- Among the options provided (mouse, rabbit, bear, fox), we need to identify the largest animal.
- The bear is the largest among these options.

6. **Conclusion**:
- Since the bear is larger, it will generate more heat and lose heat at a slower rate compared to the other smaller animals.
- Therefore, the bear would be the best at maintaining its body temperature in a cold climate.

### Final Answer:
**Bear** (Option C) is the best at maintaining its body temperature in a cold climate.

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