Read the following passage and mark the letter A, B, c, or D to indicate the correct word or phrase that best fits each of the numbered blanks. 

Air, water and soil are necessary to the survival of all living things. Badly polluted air can (6) _______illness, and even death. Polluted water kills fish and other marine life. (7) ________ of the soil reduces the amount (8) ________ land that is available for growing food. The pollution problem is very (9) _______ because much pollution is caused by things that benefit people. For example, exhaust from automobiles causes a large percentage of air pollution. (10) _________ the automobile provides transportation for millions of people.