Which of the following is NOT considered a major greenhouse gas?

In the context of greenhouse gases, nitrogen is not classified as a major greenhouse gas. Greenhouse gases are those that trap heat in the atmosphere and contribute to the greenhouse effect, leading to global warming and climate change.

Water vapor, methane, and carbon dioxide are all significant contributors to this effect. Water vapor is the most abundant greenhouse gas and enhances the effects of other greenhouse gases. Methane is much more effective at trapping heat than carbon dioxide, although it is present in smaller quantities. Carbon dioxide is a major result of human activities such as burning fossil fuels and is a primary driver of anthropogenic climate change.

Nitrogen, on the other hand, while essential for various biological processes and making up about 78% of the Earth's atmosphere, does not have the same heat-trapping properties and thus is not considered a greenhouse gas in the context of global warming. Its role in the atmosphere primarily involves maintaining pressure and supporting life, rather than contributing to the greenhouse effect.