Cold blooded animals is the one which has

Options

A. Cold blood
B. Low body temperature
C. Cold habitat
D. No regulator system of body temperature

Answer

### Step-by-Step Solution:

1. **Understanding Cold-Blooded Animals**: Cold-blooded animals, also known as poikilothermic animals, are those whose body temperature varies with the temperature of their environment. They do not have the ability to internally regulate their body temperature.

2. **Identifying Characteristics**: These animals cannot maintain a constant body temperature. Instead, their body temperature fluctuates based on external conditions. This means that in colder environments, their body temperature drops, and in warmer environments, it rises.

3. **Examples of Cold-Blooded Animals**: Common examples of cold-blooded animals include reptiles (like snakes and lizards), fish, and amphibians (like frogs and salamanders). These animals rely on environmental heat sources to regulate their body temperature.

4. **Understanding Thermoregulation**: Cold-blooded animals lack a sophisticated thermoregulation system. Unlike warm-blooded animals (homeothermic), which can maintain a stable internal body temperature regardless of external conditions, cold-blooded animals do not possess this capability.

5. **Analyzing the Options**: The question provides several options:
- A) Cold blood
- B) Low body temperature
- C) Cold habitat
- D) No regulator system of body temperature

Among these, the correct answer is **D) No regulator system of body temperature**, as it accurately describes the nature of cold-blooded animals.

### Final Answer:
**D) No regulator system of body temperature**

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