Answer:
B. Carbon Dioxide
Step-by-step explanation:
Carbon dioxide is the most abundant additive greenhouse gas contributing to global warming. It is the fourth most abundant component of dry air and levels in our atmosphere have thus risen about 40% since the onset of human industrialization, and are expected to play a troubling role in raising global temperature. Atmospheric carbon dioxide concentrations have varied substantially in the pre-human history of our planet, and have had profound impacts on global temperatures in the past.