What are fossil fuels primarily composed of?

• Carbon-rich substances

• Water-rich substances

• Nitrogen-rich substances

• Oxygen-rich substances

Which sector accounts for the highest percentage of greenhouse gas emissions in the United States?

• Transportation

• Agriculture

• Industry

• Residential

What is a major source of methane emissions according to the passage?

• Raising livestock

• Burning coal

• Using natural gas

• Deforestation

How have engines been improved over time to reduce greenhouse gas emissions?

• Made more efficient

• Made larger

• Made more powerful

• Made cheaper

What percentage of greenhouse gases in the United States is attributed to agriculture?

• 11 percent

• 24 percent

• 50 percent

• 5 percent

What is the primary reason for the increase in human activities that release greenhouse gases?

• Growing world population

• Decreasing fossil fuel reserves

• Increasing renewable energy use

• Improved technology

Which of the following is NOT a fossil fuel mentioned in the passage?

• Wood

• Coal

• Natural gas

• Oil