Which word is the best synonym for the word primitive

(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 sentence contains an allusion? a. pamela and her twin are as alike as two peas in a pod, and they do everything together. b. pamela has a weakness for chocolates, which she says she's had since early childhood. c. pamela's face was as white as a ghost when she learned the shocking news about her brother. d. pamela's backyard looks like the garden of eden, with dozens of green and lush plants. e. pamela found herself trapped between a rock and a hard place, and she didn't know what to do.

What is the main problem that kyle faces at beginning of the story