Regulators are also called

Options

A. endotherms
B. exotherms
C. ectotherms
D. either 2 or 3

Answer

To answer the question "Regulators are also called," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Regulators**: Regulators are organisms that maintain homeostasis, which is the ability to maintain a stable internal environment despite external changes.

2. **Defining Homeostasis**: Homeostasis involves maintaining constant internal conditions such as body temperature and osmotic concentration.

3. **Examples of Regulators**: The primary examples of regulators are mammals and birds. These organisms have mechanisms to keep their internal environment stable.

4. **Thermoregulation**: One key aspect of homeostasis is thermoregulation, which is the process of maintaining a constant body temperature. This is crucial for the survival of these organisms.

5. **Energy Cost of Thermoregulation**: Thermoregulation is an energetically expensive process, which is why not all organisms are regulators. Only certain groups, like birds and mammals, have this capability.

6. **Terminology**: Organisms that can regulate their internal body temperature through internal heat generation are referred to as "endotherms." This term specifically denotes those that generate heat internally to maintain their body temperature.

7. **Conclusion**: Therefore, the correct answer to the question is that regulators are also called **endotherms**.

### Final Answer:
Regulators are also called **endotherms**.

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