Which of the following gases is the major byproduct of fossil fuel combustion?sulfuric acidwater vaporcarbon dioxidemethane

The major byproduct of fossil fuel combustion is carbon dioxide.

Here's the step-by-step process of how fossil fuel combustion works:

1. Fossil fuels, such as coal, oil, and natural gas, are rich in carbon and hydrogen. When they are burned, they react with oxygen in the air.

2. The carbon in the fossil fuels reacts with the oxygen to form carbon dioxide (CO2). This is a process called oxidation.

3. The hydrogen in the fossil fuels reacts with oxygen to form water vapor (H2O).

4. Other byproducts can also be produced in smaller amounts, such as sulfur dioxide (SO2) when sulfur-rich fuels are burned. This can react with water in the atmosphere to form sulfuric acid, contributing to acid rain.

5. Methane (CH4) is a component of natural gas, and can be released during extraction and processing of fossil fuels, but it is not a major byproduct of the combustion process itself.

So, while water vapor, sulfuric acid, and methane can all be associated with the use of fossil fuels, the major byproduct of the combustion process itself is carbon dioxide.