does sound travel through vaccum ??, what is the range humans can hear at ?? , how do elephants communicate ??, How far away is the storm if the time delay between thunder and lightning is ??, what material can sound waves travel the fastest through ???, why do astronauts use walkie talkies to communicate ??, how are sounds made ?? , what form does sound energy travel in ??, what is the meaning of infrasound ?? , how is sound energy collected ?? .

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