Need help plz and thanks

(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.”)

Determine the meaning of the word *propel* using the context clues in the sentence. wind power is the ability to capture the wind in a way to *propel* the blades of wind turbines. a) to move slowly b) to urge onward c) to stop from moving d) to drive, or cause to move, forward

Read the introduction to the persuasive essay, "should cosmetic surgeries be banned? " what makes this introduction weak?