The burning of fossil fuels releases __________ gas, which builds up in the atmosphere and traps heat in. acarbon dioxide boxygen cnitrogen dmethane

The burning of fossil fuels primarily releases carbon dioxide (CO₂) gas, which builds up in the atmosphere and traps heat, contributing to the greenhouse effect and climate change. This process occurs when fossil fuels such as coal, oil, and natural gas are combusted for energy, releasing CO₂ as a byproduct.

While other gases such as methane (CH₄) and nitrogen oxides (NOₓ) are also released during fossil fuel combustion, carbon dioxide is the most significant in terms of volume and its long-lasting impact on global warming. Therefore, the correct answer to the statement is carbon dioxide.