What is the study of the history of tree rings called?

Read the paragraph below and answer the question that follows. "andy was asked to speak in a school assembly about a fundraising opportunity for a fellow student who had recently been diagnosed with leukemia. andy's stomach hurt and his hands were cold. "steady man," he thought. "you can do this. it's for tim. he needs our ." andy could picture the students wanting to get involved. it occurred to him now that he wasn't just giving a speech. he had something worthwhile to say. which strategies did andy use to reduce his apprehension? select all that apply." be prepared. use muscle relaxation techniques. get experience. think positively. focus on communicating to the audience.