Why is the cause-and-effect structure so common in expository writing?

one reason summer auggie is because she is kind, and the whole "boy war" between jack will and julian was probaly thinking her to be on auggies sode and if you read auggie and me,   she was nice to auggie because julian was mean and auggie needed some freinds. hope this

. 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.