7. There is a narrow opening from the Mediterranean to the Atlantic called the Strait of

Gibraltar. During World War II, submarines would sneak quietly through the heavily patrolled strait by shutting off their engines. Explain how the subs were able to

sneak through the strait without using their engines.

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