The following passage (paragraph7) adds to the development of the text mainly by showing

the answer to this question is unstoppable.

. a function is a relation in which each input has only one output. in the relation , y is a function of x, because for each input x (1, 2, 3, or 0), there is only one output y. x is not a function of y, because the input y = 3 has multiple outputs: x = 1 and x = 2.

a. by showing how a character reacts to or interacts with his or her   surroundings

explanation:

the setting reveal information about a character by showing how a character reacts to or interacts with his or her   surroundings.