Which of the following is the best example of a way human lifestyles affect environmental systems? O Using radioactive materials causes ground pollution as it causes methane to seep into the ground. Burning fossil fuels causes water pollution by increasing the amount of water vapor in the atmosphere. O Deforestation causes acid rain by decreasing carbon dioxide \( \left(\mathrm{CO}_{2}\right) \) in the atmosphere. Using aerosols that contain chlorofluorocarbons (CFCs) decreases the amount of protective ozone \( \left(\mathrm{O}_{3}\right) \). O \( \begin{array}{l}\text { U } \\ \text { O }\end{array} \).

To determine which option best exemplifies how human lifestyles affect environmental systems, let's analyze each statement: 1. **Using radioactive materials causes ground pollution as it causes methane to seep into the ground.** - This statement is misleading. While radioactive materials can cause ground pollution, they do not typically cause methane to seep into the ground. Methane is primarily associated with organic decomposition and fossil fuel extraction. 2. **Burning fossil fuels causes water pollution by increasing the amount of water vapor in the atmosphere.** - This statement is not accurate. Burning fossil fuels primarily contributes to air pollution and greenhouse gas emissions, but the increase in water vapor is not a direct cause of water pollution. 3. **Deforestation causes acid rain by decreasing carbon dioxide \( \left(\mathrm{CO}_{2}\right) \) in the atmosphere.** - This statement is incorrect. Deforestation actually increases \( \mathrm{CO}_{2} \) levels in the atmosphere, which can contribute to climate change but does not directly cause acid rain. 4. **Using aerosols that contain chlorofluorocarbons (CFCs) decreases the amount of protective ozone \( \left(\mathrm{O}_{3}\right) \).** - This statement is accurate. CFCs are known to deplete the ozone layer, which protects the Earth from harmful ultraviolet radiation. This is a clear example of how human activities (using aerosols) negatively impact environmental systems (the ozone layer). 5. **\( \begin{array}{l}\text { U } \\ \text { O }\end{array} \).** - This option does not provide any relevant information. Based on this analysis, the best example of how human lifestyles affect environmental systems is: **Using aerosols that contain chlorofluorocarbons (CFCs) decreases the amount of protective ozone \( \left(\mathrm{O}_{3}\right) \).**