HELP ME ASAP its really confusi nf to me

Will give read the sentence: (blank) starting to rain outside. which is the best word to complete the sentence? a : its b : its’ c : ’tis d : it’s

Which sentence best contrasts two things? a. air travel, like bus travel, is a fun way to get from one place to another. b. air travel is a fun and relatively easy way to get from place to place. c. both bus travel and air travel require substantial planning. d. air travel is much more expensive than bus travel.

(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.”)