Which sentence is the best use of passive voice?

The door was opened by Katrina when the bell was rung by Lana.
Water is formed by two molecules of hydrogen and one of oxygen.
The story was read by each person in the class, taking turns.
This paper airplane was folded by Andrea and th

(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.”)

Which type of poetry often begins by announcing the subject and asking a muse for ? a. epic poetry b. dramatic poetry c. sunnets d. ballads

Tia and lin had been best friends since kindergarten. both avid soccer players, the girls decided to try out for the high school team together. unfortunately, there was just one open spot, so only one of the girls would be chosen. they both worked hard, and on tryout day, they did their best. when the team roster came out, lin was excited to see that she had made the team but sad that tia had not. tia was happy for her friend and vowed to work harder so she would make the team the next year. which sentence is the exposition of the passage