Which of the following is NOT a greenhouse gas?

Greenhouse gases are compounds in the atmosphere that can trap heat, contributing to the greenhouse effect and influencing global temperatures. Carbon dioxide, methane, and nitrous oxide are all recognized greenhouse gases due to their ability to absorb infrared radiation.

Oxygen, however, is not a greenhouse gas because it does not absorb infrared radiation effectively. While it is a vital component of the atmosphere, playing a crucial role in respiration and combustion, it does not contribute to the greenhouse effect in the same way that the other gases do. This distinction highlights the specific roles that different gases play in Earth's atmosphere and climate dynamics.