When two fractions refer to the same whole explain why the fraction with a lesser denominator has larger pieces than the fraction with a greater denominator

Because there are less pieces the whole is split up into. For instance, if you have 1 bag of cookies, you would get more cookies per person if it was split between 2 people than if it was split between 10, because each person gets more of the whole, and there's less people to split up that whole.
since you have an equal amount of pieces from each, the whole that was split into the least pieces, or the number with the smaller denominator will be larger since the pieces will be larger