How can a speaker vary the tone of the speech?

A speaker can change the tone of speech in many ways. If a person is speaking from a podium there is like a barrier between him or her and the audience. However, the speaker can use a serious, joyful, humorous, formal, informal, gloomy, pessimistic or optimistic tone.

c.to compare several aspects of the tragedy to other worldwide tragedies

the autor of the text is bringing the point that one achievment of the president john f. kennedy was a success and this caused the next president to use a similar idea. the purposefor the use of the quotation in the text is to support the idea that peace corps was a result of the president's call. in this case, the quotation is presented as part of the writing and does not stand on its own.

answer a.