The older adult has a greater risk of dehydration because of

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Explanation:

As the body ages, the amount of water in it decreases, and this is one of the main reasons elderly adults are at a higher risk for dehydration. Whereas younger people can afford to lose more water, adults over 60 can lose the same amount and develop dehydration faster.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

that is true   : ) hope this you