What branch of science deals with the properties and behavior of water?

Hydrology is the branch of science specifically focused on the properties, distribution, and behavior of water in the environment. It encompasses the study of water's movement, its interaction with the atmosphere, the land, and living organisms, as well as its cycle through various states—such as liquid, vapor, and ice. Hydrologists investigate both surface water and groundwater, look at how water resources can be managed sustainably, and study phenomena like precipitation, evaporation, and water quality.

While biology examines living organisms and their relationships with water, and chemistry focuses on the composition, structure, and changes of matter, including water, neither of these fields centers on water as a primary subject. Physics, on the other hand, would consider the physical properties and behaviors of water on a broader level, but it lacks the specific environmental focus that hydrology offers. Thus, hydrology is the most appropriate choice when discussing the scientific exploration of water's properties and behavior.