Nikki needs to establish a more effective controlling idea in her paper. Which rewrite of sentence 8 can BEST accomplish this goal?
(4) How do all those planes stay on course without hitting one another? (5) The answer can be found in our nation’s air traffic control towers. (6) In tower after tower, behind dizzying arrays of knobs, buttons, and screens, crews of air traffic controllers are busily working. (7) These people have one of the most important jobs in the world. (8) They keep you and me safe.

