This quotation states the central idea of child's article.
in three or four sentences, explain how child
developed this idea.

i dont kmow it? !

. 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.

alpaca, a creature of myth, some say they spit fireballs out of their low hanging-saggy lips whenever they feel they're being violated.