human
Question: A hydrologist studies the location, movement, and quality of water. A hydrologist recognizes the importance that water exists as ___.

Choices:
A) a solid, a liquid, and a gas (vapor)
B) a solid and a liquid
C) a solid and a gas (vapor)
D) a solid only
gpt
The correct answer is 0: a solid, a liquid, and a gas (vapor).