Which of the following cause indirect Green House Warming? Choose the correct answer from the options given below.

Indirect greenhouse warming comes from gases that do not trap heat directly but foster the formation of other warming agents, here nitric oxide, nitrogen dioxide and carbon monoxide.

Statement 2 holds because nitric oxide promotes tropospheric ozone, an indirect warming effect.

Statement 3 holds because nitrogen dioxide similarly aids ozone formation in the lower air.

Statement 5 holds because carbon monoxide extends the life of methane and helps make ozone.

Statement 1 is excluded because methane is a direct greenhouse gas that absorbs heat itself.

Statement 4 is excluded because nitrous oxide is likewise a strong direct greenhouse gas.