What is the symbol for standard deviation?

Read this excerpt from leah missbach day's foreword to wheels of change.bicycles have long played a role in my life. as a young woman, i rode one year-round before i had a car. but it was later in adulthood that the bicycle became more than a source of transportation for me. the bicycle actually began to truly shape the way i saw the world.what is the author's purpose for including this in the foreword?

Returning from vietnam, we were indeed given a parade. crowds of screaming people waving signs — not just on one road, one day. no, they were everywhere. every day. on the streets, on the television, on the radio. a hot, angry tangle of shaking fists and ugly words that threatened us like a monster with a hundred heads. our country had chewed us up and spit us out, and now we were being treated as if it were our fault. what is one way the author's use of language contributes to the tone of this passage? a. the use of figurative language creates a feeling of resentment. b. the phrase "hot, angry tangle" is used sarcastically to create irony. c. the word "parade" is used sarcastically to create a lighthearted mood. d. the parallelism draws attention to the confusion of those returning.

Answer 7th question pls asap i need