Take Grist's Green Quiz

I correctly answered just 4 out of 11! Maybe you can do better. I'll spot you an answer to give you a head start.

If every American household replaced five incandescent light bulbs with higher-efficiency bulbs (like compact fluorescents -- aka CFLs), how many pounds of greenhouse gases would be kept out of the air?

The correct answer: 1 trillion

Solution: Lightswitch engage! Swap out all your light bulbs to CFLs, and encourage your friends and fam to do the same. You'll save money, because they last longer and use less energy. Besides, Pink Floyd sounds better in the dark anyway. Click here to learn more about the benefits of replacing your light bulbs.