How is treating someone like they're invisible a form of racism?

(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.”)

Is the group of words a simple sentence, a compound sentence, or a run-on sentence? jan went on a quiz show, won two hundred dollars, and bought gifts for her family. a. run-on sentence b. compound sentence c. simple sentence

Identify the sentence in which the underlined word or words are punctuated incorrectly. a) pam was (well prepared) for the debate. b) she had (read three quarters) of the material more than once. c) she has always been (self assured). d) the winner needs a (two-thirds) majority of the votes.