4)
Which fact does the passage leave uncertain?
A) what season the story is set within
B) what sort of condition the road is in
C) why the man and woman aren't speaking
D) what time of day the story occurs within

(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.”)

What is the answer to this question

Use a subordinate conjunction to combine these two sentences into one sentence. the journalist met a source at the hotel. this way he would get facts for an article.