Fact 1: Asolution is formed by one substance being dissolved in another substance. Fact 2: Another dissolved substance in ocean water is a type of rock called limestone . Given the two facts above, a solution is formed when limestone is dissolved in what?

Possible answers:
(I) old caves
(II) habitats
(III) body water
(IV) rainfall
(V) calcite
(VI) sandy shores
(VII) evaporation
(VIII) ocean water
The answer is:
(VIII)