Answer:
it's the last one, all of the others don't make enough sense
Natural environment has the ability to gather some pollutants yet if too much then the environment could no longer handle it. A leaky sewage can pollute an aquifer with I. arsenic as the contaminant. Arsenic is a metalloid existing in the Earth's crush. Exposure is natural yet can be aggravated by the human activities.
Yes
SIMPS ALL RISE TO THE KING
what are you talking about