What is the root word for greenhouse gas?

Greenhouse gases (GHG) include carbon dioxide, water vapor, methane, ozone, nitrous oxide and fluorinated gases. These molecules in our atmosphere are called greenhouse gases because they absorb heat. Thus, greenhouse gases trap heat within the surface-troposphere system.

[From green +‎ house ("house for growing greens"), in reference to the produce grown within.]

the answer your looking for is c. : )

well it depends i think people around the world are coming around to gay marriage. but if you are talking abortion then wow, so much to talk about. such as men thinking they have the right to choose if women can, the fact there are health concerns if the women can't get one, and many more arguments to discuss. so i would definitely say abortion would be a much more interesting topic.