Question: Many scientists accept the theory that excess emission of carbon dioxide from cars and industry causes a layer of gas in the upper atmosphere that traps heat. This, in turn, causes the average temperature on Earth to rise. Which of the following observations supports that theory?

  Options: 
 A. The summer of 1998 was one of the hottest summer seasons on record.
 B. Carbon dioxide gas from cars and industry is a product of burning that produces heat.
 C. Carbon dioxide in the upper atmosphere reflects heat radiated from Earth's surface.
 D. Radiation on Earth's surface is increasing because of a hole in the ozone layer
Answer: C