Which of the following is NOT a greenhouse gas?

Nitrogen

The correct answer is option 1. Nitrogen.

The gas listed that is NOT a greenhouse gas is Nitrogen.

Nitrogen \((N_2)\) is not considered a greenhouse gas. While it is abundant in Earth's atmosphere, nitrogen molecules do not significantly contribute to the greenhouse effect. Greenhouse gases are those that absorb and emit infrared radiation, trapping heat in the Earth's atmosphere. Nitrogen does not possess this property to a significant extent.