Which activity is most likely to contribute to the greenhouse effect?

The activity that most significantly contributes to the greenhouse effect is the burning of fossil fuels for energy. Fossil fuels, such as coal, oil, and natural gas, release large amounts of carbon dioxide (CO2) and other greenhouse gases when they are combusted. These gases accumulate in the atmosphere and trap heat, leading to an increase in global temperatures—a process known as the greenhouse effect.

In contrast, using a bicycle as primary transportation reduces dependence on fossil fuels, contributing to lower greenhouse gas emissions. Planting trees for carbon sequestration actively removes CO2 from the atmosphere, and implementing recycling programs helps reduce waste and can lead to lower energy consumption and emissions associated with manufacturing new products. Each of these alternatives either mitigates or counteracts the release of greenhouse gases, making them less impactful on the greenhouse effect compared to the combustion of fossil fuels.