Q: Fact 1: Carbon dioxide concentrations in the air have increased over the last decade dramatically. Fact 2: Carbon dioxide is the primary greenhouse gas. Given the two facts above, what have increased over the last decade dramatically?

Select from: + gasoline concentrations. + Warm air moving into cold air. + Greenhouse gases. + treehouse gas concentrations. + movements in the earth's crust. + concentrated orange juices. + genetic diversity. + greenhouse gas concentrations.
A:
greenhouse gas concentrations