TOEFL Listening: TPO-TOEFL听力TPO - 3I70WX1F7NBG9M89R$

What is the main purpose of the lecture? A. To argue that carbon emissions today are not the only factor responsible for global warming B. To provide evidence that rates of global carbon emissions fluctuate over time C. To show the importance of distinguishing between different types of carbon emissions D. To describe different ways carbon is removed from the atmosphere