Some animals have constant high body temperature . This is because

Options

A. they can work fast at this temperature
B. they prefer to live in cold region
C. they are active animals
D. they like this temperature.

Explanation

To solve the question "Some animals have constant high body temperature. This is because," we need to analyze the given options and determine which one correctly explains the phenomenon of constant high body temperature in some animals.

### Step-by-Step Solution:

1. **Analyze Option A: They can work fast at this temperature.**
- While it is true that some animals are more active at higher temperatures, this does not explain why only some animals have a constant high body temperature. If this were the case, we would expect all animals to adapt to a high body temperature, which is not the case. Therefore, this option is not correct.

2. **Analyze Option B: They prefer to live in cold regions.**
- Animals that live in cold regions need to maintain their body temperature above the surrounding cold environment to ensure proper physiological functions. This adaptation allows them to remain active and perform necessary biological processes despite the cold. Thus, this option is a strong candidate for the correct answer.

3. **Analyze Option C: They are active animals.**
- While it is true that many animals are active, being active does not necessarily require a high body temperature. There are many active animals that do not have a constant high body temperature. Therefore, this option is not correct.

4. **Analyze Option D: They like this temperature.**
- This option is subjective and does not provide a scientific basis for why some animals have a constant high body temperature. Animals do not "like" temperatures; they adapt to their environments. Thus, this option is also incorrect.

### Conclusion:
After analyzing all the options, the correct answer is **Option B: They prefer to live in cold regions.** This explains that these animals need to maintain a high body temperature to compensate for the cold environment they inhabit.