Driving a car is the most carbon-intensive form of transportation, as it releases greenhouse gases such as carbon dioxide and methane into the atmosphere.

Reducing meat consumption can help reduce your carbon footprint by reducing the demand for meat production, which in turn reduces land and water use, methane emissions, and deforestation.

Solar energy has the lowest carbon footprint among the given options, as it does not produce greenhouse gases during electricity generation.

Energy efficiency refers to the practice of using less energy to perform the same task, while energy conservation involves reducing energy consumption by changing habits or behaviors.

Using public transportation, eating locally-sourced food, and recycling and composting waste are all examples of lifestyle choices that can help reduce your carbon footprint.

Afforestation refers to the practice of planting trees in areas that were previously not forested, while reforestation involves planting trees in areas that were previously forested but have been cleared.

Nitrogen is not a greenhouse gas, as it does not trap heat in the atmosphere like carbon dioxide, methane, and water vapor do.

Carbon offsetting involves investing in projects that reduce or remove carbon from the atmosphere, such as planting trees or investing in renewable energy projects.

Solar energy is a renewable energy source, as it is derived from the sun's energy and does not produce greenhouse gases during electricity generation.

Energy conservation involves reducing energy consumption by changing habits or behaviors, such as turning off lights when leaving a room or unplugging electronic devices when not in use.

Coal is a non-renewable energy source, as it is derived from fossil fuels that are formed over millions of years and cannot be replenished.

Carbon offsetting involves investing in projects that reduce or remove carbon from the atmosphere, such as planting trees or investing in renewable energy projects.

Using public transportation, eating locally-sourced food, and recycling and composting waste are all examples of lifestyle choices that can help reduce your carbon footprint.

Energy efficiency refers to the practice of using less energy to perform the same task, while energy conservation involves reducing energy consumption by changing habits or behaviors.

Walking has the lowest carbon footprint among the given options, as it does not involve the use of motorized vehicles and does not produce greenhouse gases.