Question

____ is the only substance to naturally exist in all three forms of matter: solid, liquid,
iron
copper
water
carbon

Explanation:

We know from the study of matter and its states (solid, liquid, gas) that water can exist as ice (solid), liquid water, and water vapor (gas) naturally on Earth. Iron, copper, and carbon do not naturally exist in all three states under normal Earth conditions.

Answer:

C. Water