Dogs stretch out tongues generally in summer because

Options

A. evaporation lead cooling.
B. of condensation of water vapour.
C. of freezing of saliva.
D. their body temperatures are high.

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks why dogs stretch out their tongues during the summer.

2. **Identifying the Mechanism**: Dogs stretch out their tongues to cool down. This is a behavior observed in many animals, especially in hot weather.

3. **Role of Saliva**: When dogs stretch out their tongues, saliva on their tongues is exposed to the air.

4. **Evaporation Process**: The saliva undergoes evaporation. Evaporation is the process where liquid turns into vapor, which requires heat.

5. **Cooling Effect**: As the saliva evaporates, it absorbs heat from the dog's body, leading to a cooling effect. This helps in reducing the body temperature of the dog.

6. **Conclusion**: Therefore, dogs stretch out their tongues in summer because the evaporation of saliva cools their body.

### Final Answer:
Dogs stretch out their tongues generally in summer because the evaporation of saliva from their tongues leads to cooling, which helps to decrease their body temperature.

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