Hi

air and water pollution have been reduced by

a. increasing biological magnification.
b. raising more cattle for food.
c. using only unleaded gasoline.
d. using fossil fuels in factories

you !

C. using only unleaded gasoline.

Explanation:

The unleaded gasoline is devoid of lead, this prevents the engines of the vehicles from getting damaged. Also the leaded gasoline or lead containing fuel emits harmful gases to the atmosphere after combustion. These gases can cause harmful diseases in humans and animals. But unleaded gasoline does not emit such harmful gases to air. This will prevent the pollution of air. Also the water body will remain protected against the pollution as the harmful gases liberated from leaded gasoline may dissolve in water.

the real answer is b. scintillation counter