HELP ASAP PLS !

In the dramatization of Dragonwings, Uncle Bright Star says, "That hill is a very steep hill. Which does Windrider's response signify?
Windrider wants to start on the highest hill to have the longest flight down.
Windrider wants to pull it up the steep hill because "the winds are right.".
Windrider wants to see how Uncle and the others will get the plane up the
Windrider wants to see what's on top of the very steep hill.

What sentence correctly uses it’s underlined relative pronoun?

(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.”)

The overwhelming majority of the peoples and nations of the world today want to live in peace