PPSC Past Paper Assistant in S&GAD Department, 2018 Solved MCQs, Everyday Science MCQs, PPSC Solved Past Papers MCQsGreen House effect is mainly caused by excess of _____? Posted on June 16, 2021 by Rana TahirA. Carbon dioxide B. Carbon monoxide C. Nitrogen D. Hydrogen sulfideShare this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on WhatsApp (Opens in new window)Click to share on Pinterest (Opens in new window)Click to share on LinkedIn (Opens in new window)