Everyone wants to reduce (1) _______. But the pollution problem is as complicated as it is (2) _______. It is complicated because much pollution is caused by things that benefit people. For example, (3) _______ from automobile caused large (4) _______ of air pollution. But the automobile provides transportation to millions of people. (5) _______ discharge much of the material that pollutes air and water, but factories give employment to a large number of people. Thus, to end or greatly (6) _______ pollutions immediately, people would have to stop using many things that benefit them. Most people do not want to do that, of course. But pollution can be gradually reduces in several ways, (7) _______ and engineers can work to find ways to lessen the amount of pollution that such things as automobiles and factories cause. Government can pass and enforce laws that (8) _______ businesses and individuals (9)______ stop, or cut down (10)_______certain polluting activities.