Scientists have determined that the amount of carbon dioxide in the atmosphere can be modeled by the equation y = 2x + 368, where x is the number of years since the turn of the century and y is the amount of carbon dioxide in parts per million. Which of these statements is correct according to the model? A.
Every year the amount of carbon dioxide in the atmosphere increases by 2 parts per million.

B.
Every 2 years the amount of carbon dioxide in the atmosphere increases by 1 part per million.

C.
Ten years from now there will be 5 more parts per million of carbon dioxide in the atmosphere than there are now.

D.
Ten per million of carbon dioxide in the atmosphere.