What are two advantages of setting up instruments for measuring carbon dioxide on top of mauna loa

So it's easier to understand how plants take in carbon-dioxide and how much carbon-dioxide is in the atmosphere

well we can't tell you because we cant see the time give a screen shot or something.

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.