Answer:
The researchers wanted to know how well the average American understands the basic processes responsible for global warming, and whether there's a relationship between this basic understanding and the belief that global warming is actually occurring.
The results were sobering. While a majority of volunteers believed that global warming is a reality (80 percent) and that human activities are a significant contributing factor (77 percent), only a slim minority was able to explain even rudimentary aspects of the mechanism. Twelve percent referenced gases in the atmosphere that trap heat (such as pollution or carbon dioxide), and of these, none addressed a puzzle that this partial answer seems to raise: why gases that trap heat in the earth's atmosphere don't similarly block heat from entering the atmosphere in the first place.
