OPTIONS:
(I). Calcium carbonate
(II). evaporation
(III). circulatory systems
(IV). sugar
(V). chlorine bleach
(VI). one celled organisms
(VII). glass
(VIII). cyanide

Fact 1: Treating water is used to remove harmful substances before drinking. Fact 2: Chlorine bleach is ideal for treating water. Given the two facts above, what removes harmful substances from water before drinking?
Answer:
(V).