Treating water is used to remove harmful substances before drinking.
Arsenic, a naturally occurring substance, contaminates water sources in many countries.
Treating water is used to remove arsenic before drinking.
What is treating water used to remove before drinking?

(a) arsenic
(b) air
(c) cellulose
(d) chemicals
(e) Collagen
(f) loose dirt
(g) water vapor
(h) ice