Which of the following is a greenhouse gas that affects climate change?

Carbon dioxide is a greenhouse gas that significantly affects climate change due to its ability to trap heat in the atmosphere. This process helps regulate the Earth's temperature, but an increase in carbon dioxide levels—primarily from human activities such as burning fossil fuels, deforestation, and industrial processes—intensifies the greenhouse effect. As more heat is trapped, it leads to global warming and associated climate changes, such as extreme weather events and rising sea levels.

The other options, while important for various aspects of life and environmental processes, do not serve the same role in climate change. Nitrogen, while a major component of the atmosphere, is largely inert and does not significantly contribute to climate dynamics. Oxygen is essential for respiration and combustion but does not trap heat effectively. Hydrogen, although a clean energy carrier, is not a greenhouse gas and does not contribute to the greenhouse effect. Therefore, carbon dioxide stands out as a key driver of climate change among the listed options.