How does an artificial pacemaker work?

A pacemaker helps monitor and control your heartbeat. The electrodes detect your heart's electrical activity and send data through the wires to the computer in the generator. If your heart rhythm is abnormal, the computer will direct the generator to send electrical pulses to your heart.

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.

i think that is new experiments yield untrustworthy data and should be carefully considered, because you don't know what will happen with the experiments.