The correct answer is D. increases levels of greenhouse gases
Explanation
Greenhouse gases are a group of gases present in the atmosphere such as carbon dioxide, methane, ozone, water vapor, chlorofluorocarbons, among others, and what they cause in the atmosphere is a greenhouse effect, that is, they trap two thirds of the sun's rays and retain them within the Earth's atmosphere. These gases are thereby natural processes of the earth; however, with the increase in emission of gases by combustion of fossil fuels some greenhouse gases have increased their percentage in the atmosphere, especially carbon dioxide. This causes the temperature increase in the earth's atmosphere by the retention of solar rays in greater quantities. So, the correct answer is D. Increases levels of greenhouse gases.
