Q: What gas produced by fossil fuel use is a major cause of global warming?


Read this paragraph and choose the correct option from the provided answers:

When fossil fuels burn, they release thermal energy, water vapor, and carbon dioxide. Carbon dioxide produced by fossil fuel use is a major cause of global warming. The burning of fossil fuels also releases many pollutants into the air. Pollutants such as sulfur dioxide form acid rain, which kills living things and damages metals, stonework, and other materials. Pollutants such as nitrogen oxides cause smog, which is harmful to human health. Tiny particles, or particulates, released when fossil fuels burn also harm human health. Natural gas releases the least pollution; coal releases the most (see Figure below ). Petroleum has the additional risk of oil spills, which may seriously damage ecosystems.

 Choices:

- helium

- hydrogen

- phosphorous

- carbon dioxide


A:
carbon dioxide