Computer programs can be classified into two broad categories. what are those categories?

Answer : The computer programs can be broadly classified into two categories namely;

i) Application software which is the general designation of computer programs for performing tasks.

ii) System software is a generic term referring to the computer programs which is used to start and run computer systems including diverse application software and networks.

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.