Which of these sentences uses correct punctuation?

How does thoreau defend his approach in the second paragraph of "economy" inwalden? -he uses the word "t" because he feels it sounds more interesting-he does not use first-person point of view because his is a fictional account-he uses first-person point of view to get his readers' attention-he uses the word "t" for the sake of sincerity and honesty.

What is a mechanism by which organisms maintain homeostasis when the level of one substance influences the level of another substance or the activity of an organ.

You were given an exceptional iq so obviously you made valedictorian to change the tone of the sentence from resentful to complimentary, without changing the central meaning, which word most needs to be replaced? o a. exceptional o b. valedictorian o c. given o d. obviously