The animals of cold countries have relatively shorter and poorly developed ears, eyes, hairs and other, phenotypic characters, This is known by which law?

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question refers to animals in cold climates that exhibit shorter and poorly developed extremities, such as ears, eyes, and hairs. We need to identify the law that explains this phenomenon.

2. **Identifying the Phenomenon**: The phenomenon described involves the adaptation of animals to cold environments. In such climates, animals tend to have shorter extremities to minimize heat loss.

3. **Relating to Biological Laws**: There are several biological laws that explain adaptations in animals. One of the most relevant in this context is Allen's Law.

4. **Explaining Allen's Law**: Allen's Law states that endothermic (warm-blooded) animals in colder climates tend to have shorter limbs and extremities compared to those in warmer climates. This adaptation helps to conserve body heat.

5. **Conclusion**: Based on the explanation of Allen's Law and its relevance to the question, we conclude that the phenomenon of shorter extremities in animals from cold countries is described by Allen's Law.

**Final Answer**: Allen's Law

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