(a) radon (b) mercury (c) lead (d) copper (e) iron 1. was once widely used in the united states as a gasoline additive 2. a gaseous decay product of uranium that is found in rocks 3. a leading cause of lung cancer in the united states 4. poses a health risk to humans who eat large quantities of marine fish such a

Answers

1. Lead was once widely used in the United States as a gasoline additive but it was banned due to health risk.

2. Radon is a radioactive gaseous decay product of uranium that is found in rocks, soil and water.

3. Radon is a leading cause of lung cancer in the United States because the by-product of this can get trapped in the lungs.

4. Mercury poses a health risk to humans who eat large quantities of marine fish such a tuna and swordfish.