Which of the following statements about mercury is false?
a. methyl mercury compounds are unusual in that they cannot cross the body's blood-brain barrier.
b. significant amounts of mercury are released into the environment during the smelting of other metals.
c. human exposure to mercury is primarily by eating marine animals containing high levels of mercury.
d. methyl mercury compounds are more toxic forms of mercury that readily enter the food web.
e. methyl mercury compounds persist in the environment for a long time.

Option (A).

Explanation:

The element mercury can persist in the environment and proves to be harmful for the living organism. The mercury persist in the lower organism and transfer to the higher organism by the process of biological magnification.

The compounds of methyl mercury are not harmful. The methyl mercury compound cannot cross the blood-brain barrier and does not affect the individual.

Thus, the correct answer is option (A).

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.