_____ causes melting of polar ice caps and floods of low-lying coastal areas.

Options

A. Global warming
B. Eutrophication
C. Greenhouse gas
D. Acid rain

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks for the cause of the melting of polar ice caps and flooding of low-lying coastal areas.

2. **Identifying the Main Concept:**
The phenomenon that leads to the melting of polar ice caps and flooding is known as global warming.

3. **Defining Global Warming:**
Global warming refers to the increase in the average temperature of the Earth's surface due to the rising concentration of greenhouse gases in the atmosphere.

4. **Explaining Greenhouse Gases:**
Greenhouse gases, such as carbon dioxide (CO2), methane (CH4), and water vapor, trap heat in the atmosphere, leading to an increase in temperature.

5. **Connecting Global Warming to Ice Caps and Flooding:**
As the Earth's temperature rises, polar ice caps begin to melt. This melting contributes to rising sea levels, which can flood low-lying coastal areas.

6. **Conclusion:**
Therefore, the correct answer to the question is "global warming," as it is the primary cause of the melting of polar ice caps and flooding of low-lying coastal areas.

**Final Answer:**
Global warming causes melting of polar ice caps and floods of low-lying coastal areas.

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