________rule states that mammals from colder climates generally have shorter ears and limbs to minimise heat loss.

Options

A. Allen's
B. Berger's
C. Borger's
D. Powell's

Explanation

**Step-by-Step Solution:**

1. **Identify the Rule**: The question asks for a specific rule related to mammals in colder climates. The correct term is "Allen's Rule."

2. **Understanding Allen's Rule**: Allen's Rule states that mammals from colder climates generally have shorter ears and limbs compared to those from warmer climates. This adaptation helps to minimize heat loss.

3. **Explain the Adaptation**: In cold environments, mammals need to conserve body heat. Shorter extremities (like ears and limbs) reduce the surface area through which heat can escape, helping maintain a stable internal body temperature.

4. **Relate to Thermoregulation**: Mammals are warm-blooded (homeotherms) and can regulate their body temperature. If they lose heat too quickly, they would need to expend more energy to maintain their body temperature, which is not sustainable.

5. **Conclusion**: Therefore, the answer to the question is that "Allen's Rule" states that mammals from colder climates have shorter ears and limbs to minimize heat loss.

**Final Answer**: Allen's Rule

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