Why would two different authors who are writing about the same topic present it in two different ways? A. because all authors have a different purpose and style B. because the two authors cannot use the same resources C. because one author's point of view is subjective and the other's is objective
D. because all authors have to avoid plagiarism

(1) fire extended humans’ geographical boundaries by allowing them to travel into regions that were previously too cold to explore. (2) it also kept predators away, allowing early humans to sleep securely. (3) fire, in fact, has been a significant factor in human development and progress in many ways. (4) other obvious benefits of fire are its uses in cooking and in hunting. (5) probably even more important, however, is that learning to control fire allowed people to change the very rhythm of their lives. (6) before fire, the human daily cycle coincided with the rising and setting of the sun. (7) with fire, though, humans gained time to think and talk about the day’s events and to prepare strategies for coping with tomorrow. the sentence that expresses the main idea is: (type the number of the sentence. then click “go.”)

“third, all reviewers have a bias – no matter how impartial they try to be, opinions on movies are just that: opinions. this isn’t necessarily a bad thing: if you read a review by a critic that you know prefers foreign films, you know how seriously you should take his scathing critique of ironman.” according to this passage, all reviewers a. prefer foreign films c. have bias b. hated the movie ironman d. refuse to watch popular films

Lines 47–56: determine the central idea of these lines