Suppose two students grab an end of a rope. Both shake the rope once, but one makes a crest and the other a trough traveling at each other. What would
you see when the crest and trough meet? What type of interference does this show?

Which of the following is a direct benefit of the use of assembly lines in production a. laws against theft fraud and coercion are needed to protect free choice. b. the government needs to plan efficient outcomes. c. competition among producers by itself cannot ensure a wide range of consumer choices. d. works pressure the government to guarantee minimum wages