Give three instantaneous scale (time) examples of earth's systems, two long-term scale (time) examples of earth's systems, and three examples of cycles of earth's systems. why are volcanoes and volcanic activity a good example of system interactions? (site 1)

i think the miocene epoch spans the time from 23 million to 12 million years ago.

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.