Animals having a bulb-in thermostat to maintain constnat body temperature are known as

Options

A. biothermic
B. poikilothermic
C. oligothermic
D. homeothermic

Answer

To answer the question "Animals having a bulb-in thermostat to maintain constant body temperature are known as," we will analyze the options provided and determine the correct term.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the classification of animals that maintain a constant body temperature, which is a key characteristic in biology.

2. **Analyzing the Options**:
- **Biothermics**: This term refers to animals that can tolerate both cold and hot temperatures. They do not maintain a constant body temperature but can survive in varying conditions. Thus, this option is incorrect.

- **Microthermics**: This term indicates animals with variable body temperatures that change according to the external environment. They do not maintain a constant body temperature. Therefore, this option is also incorrect.

- **Oligothermics**: This term refers to animals that can only survive in low-temperature environments. They do not maintain a constant body temperature, making this option incorrect as well.

- **Homeothermics**: This term describes animals that can maintain a constant body temperature regardless of environmental changes. This is the defining characteristic of homeothermic animals, making this option the correct answer.

3. **Conclusion**: The correct answer to the question is **homeothermics**.

### Final Answer:
Animals having a bulb-in thermostat to maintain constant body temperature are known as **homeothermics**.