Identify the true statement among the following.

Options

A. CO is a greenhouse gas.
B. Global warming decreases the fertility of soil.
C. Global warming causes melting of ice caps.
D. Acid rain causes unseasonal rains.

Explanation

To identify the true statement among the given options, we will evaluate each option one by one:

1. **Option 1: CO is a greenhouse gas.**
- Carbon monoxide (CO) is not classified as a greenhouse gas. Greenhouse gases include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), which contribute to the greenhouse effect and global warming. Therefore, this statement is **false**.

2. **Option 2: Global warming decreases the fertility of soil.**
- Global warming refers to the increase in Earth's average temperature due to greenhouse gas emissions. While climate change can affect agricultural practices and soil health, the statement that global warming directly decreases soil fertility is not universally true. Therefore, this statement is also **false**.

3. **Option 3: Global warming causes melting of ice caps.**
- Global warming leads to an increase in Earth's temperature, which causes polar ice caps and glaciers to melt. This is a well-documented phenomenon and is a significant consequence of climate change. Therefore, this statement is **true**.

4. **Option 4: Acid rain causes unseasoned rains.**
- Acid rain is caused by pollutants like sulfur dioxide and nitrogen oxides, which can lead to various environmental issues, but it does not directly cause unseasoned rains. Therefore, this statement is **false**.

Based on the evaluation of all options, the true statement is:

**Option 3: Global warming causes melting of ice caps.**