(1) A gust of wind whooshes through the trees, and footsteps crunch across leaves on the ground. (2) These are just a few of the sounds filmgoers hear when watching a movie. (3) Most people assume all of the sounds they hear during movies were recorded during filming, but that isn’t always the case. (4) They are usually made after filming by special artists.
Which of the following should replace sentence 4 to effectively state the controlling idea of this paper?