C. exocytosis (I have to use 20 characters to respond and "answer it well". Exo means out/outside and exocytosis is an active transport system where a cell uses energy to transport material, like protein or waste, from inside a cell to the outside.)
Answer: Global warming is happening because the greenhouse gases are becoming more thicker which makes more of the suns radiation (heat) stay in the earth; as a result, this is increasing the earth's temperature.
The subject is geography :)
Explanation:
