Final answer:
Water exists as a solid (ice), liquid, and gas (vapor), making it the correct answer to which substance can be found in all three states at reasonable temperatures. The answer is c. water.
Step-by-step explanation:
Water, with the chemical formula H2O, is one of the few substances that exist in a solid, liquid, and gas at reasonable temperatures. At low temperatures, water exists as ice, a solid. As temperature increases, it becomes a liquid, and at high temperatures, water transitions to its gaseous form, water vapor. These three forms represent the three states of matter.
The correct answer to the question is: c. water. Unlike other options such as alcohol, oxygen, and aluminum, water uniquely exhibits the three states of matter—solid, liquid, and gas—under common environmental conditions on Earth. Water's physical properties, its high heat capacity, and high heat of vaporization also allow for these states to be readily accessible and observable.