HELP QUICK PLEASE! What determines the boundaries of a watershed?

A.
elevation features like hills, mountains, and ridges
B.
placement of cities and urban sprawl
C.
man-made boundaries like drainage ditches and reservoirs
D.
average annual rainfall in the area

All organisms contribute some water to the water cycle by conducting

Ascientist is conducting an investigation that involves water, silver, carbon dioxide, and oxygen gas which group of statements best describes all of the materials he is using in the investigation?

For the strategies below, decide whether they are best described as demand-side solutions or supply-side solutions to meeting human needs for fresh water. remember that a demand-side solution reduces demand for fresh water, whereas a supply-side solution increases the supply of fresh water. (a) damming a river to create a reservoir (b) desalinating seawater (c) a nation invading a neighboring country to access their rivers (d) raising water prices for consumers and businesses (e) providing tax breaks for companies that use less water (f) replacing inefficient irrigation with more-efficient drip irrigation to grow crops (g) requiring low-flow showerheads in all new homes