Firemen crawl when entering a burning building because

Options

A. it is easier to crawl
B. smoke rises high in the air
C. it helps to move faster
D. to resist more heat

Answer

**Step-by-Step Solution:**

1. **Understanding the Environment**: When firemen enter a burning building, they encounter smoke and heat. The smoke produced during a fire is harmful and can be toxic.

2. **Behavior of Smoke**: Smoke is lighter than air, which causes it to rise. This means that the highest concentration of smoke will be at the upper levels of a room or building.

3. **Crawling Technique**: To avoid inhaling the toxic smoke, firemen crawl on the ground. By doing so, they reduce their vertical height and stay closer to the floor where the air is clearer and less contaminated.

4. **Health Risks**: Inhaling smoke can lead to serious health risks, including suffocation or poisoning from harmful gases like carbon monoxide and nitrogen. Crawling helps them to minimize these risks.

5. **Conclusion**: Therefore, the reason firemen crawl when entering a burning building is primarily because smoke rises high in the air, allowing them to avoid the most dangerous smoke levels.

**Final Answer**: Firemen crawl when entering a burning building because smoke rises high in the air.

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