Toxic Elements Such as Mercury and Arsenic Are Found in the Human

Multiple Choice

Toxic elements such as mercury and arsenic are found in the human body because

A) of contamination from the environment.
B) trace amounts of these elements have vital biological functions.
C) they are needed to kill bacteria.
D) they may be ingested with food but inactivated by cells.
E) in small amounts they are biologically inactive and tolerated by cells.