Which of the Following Is True of Carbon Dioxide

Which of the following is true of carbon dioxide?

A) it is unimportant in regulating the temperature of the planet.
B) it is a natural product of life processes (i.e. ,respiration) .
C) it occurs in large amounts in the atmosphere-as one would expect given the important role it plays in life processes and in regulating the temperature of the planet.
D) the amount of carbon dioxide has decreased as a result of human activities.
E) it is unrelated to industrial manufacturing on Earth.