Please choose the correct answer to the question: A hydrologist studies the location, movement, and quality of water. A hydrologist recognizes the importance that water exists as ___.

Answer1: a solid, a liquid, and a gas (vapor) Answer2: a solid and a liquid Answer3: a solid and a gas (vapor) Answer4: a solid only

Answer format: answer1/answer2/answer3/answer4
Answer: answer1