Fill in the blanks with the word that best completes each statement. scientists develop knowledge by making about the natural world that may lead to a scientific question. a scientific question may lead to a(n) , which can be tested. the results of can lead to changes in scientific knowledge.

How is it possible for someone to put an ear to a wall and hear someone in the next room?     a.sound waves can travel though solids.    b.the waves travel from room to room via air.    c.there must be some air in the wall so the sound can travel through it.    d.sound waves change to electromagnetic waves and then back again.