ivement of the progress bar may be uneven because questions can be worth more or less (including zero ) depending on y Which of the relations given by the following sets of ordered pairs is a function? {(1,2),(2,3),(3,4),(5,6),(2,1)} {(-2,5),(7,5),(-4,0),(3,0),(1,-6)} {(3,-3),(3,-1),(3,1),(3,3),(3,5)} {(2,-8),(1,-4),(0,0),(1,4),(2,8)}