Answer:

Allens law states that animals living in cold regions tend to have relatively shorter and poorly developed extremities such as ears, eyes, hair, and other phenotypic characters.

Explanation:

1. Allens law:
Allens law is a biological principle that states that animals living in colder climates tend to have relatively smaller extremities compared to those living in warmer climates. This law was proposed by the American biologist Joel Asaph Allen in 1877.

2. Phenotypic characters:
Phenotypic characters refer to the observable physical traits or characteristics of an organism. These traits can include body size, shape, coloration, appendage length, etc.

3. Adaptation to cold environments:
Animals living in cold regions face challenges such as low temperatures and reduced food availability. To cope with these conditions, they have evolved certain adaptations to increase their chances of survival. One such adaptation is the reduction in size and development of certain phenotypic characters.

4. Shorter extremities:
In cold environments, it is important for animals to minimize heat loss. Animals with shorter extremities, such as ears and tails, have a smaller surface area through which heat can be lost. This helps in reducing heat loss and conserving energy.

5. Poorly developed eyes, hair, and other characters:
Similarly, animals in cold regions may have poorly developed eyes, hair, and other phenotypic characters. This can be advantageous in reducing heat loss as well as adapting to the specific environmental conditions of their habitat.

6. Examples:
Examples of animals that exhibit the principles of Allens law include the Arctic fox, which has shorter ears and limbs compared to its relatives in warmer regions, and the polar bear, which has a shorter snout and smaller ears compared to other bear species.

In conclusion, Allens law states that animals living in cold regions tend to have relatively shorter and poorly developed extremities, eyes, hair, and other phenotypic characters. This adaptation helps them to conserve heat and survive in their cold environments.

Ans: b Allen's law