Heat loss or heat gain is a function of surface area Very ________ animals are rarely found in polar regions.

Explanation

**Step-by-Step Solution:**

1. **Understanding Heat Loss and Surface Area**:
- Heat loss in animals is influenced by their surface area. The larger the surface area, the more heat an animal loses to the environment. This is due to the principle of thermoregulation, where heat exchange occurs through the skin.

2. **Identifying the Types of Animals**:
- Small animals have a relatively large surface area compared to their volume. This means they lose heat more rapidly than larger animals, which have a smaller surface area relative to their volume.

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