Pizza is a ____ mixture of dough, sauce, cheese, and other toppings.
heterogeneous mixture
A heterogeneous mixture is simply any mixture that is not uniform in composition. It is made of different substances that remain physically separate and are can usually be identified. In the case of pizza, it is a heterogeneous mixture of dough, sauce, cheese and other toppings as the composition are not that uniform and the various components used in the pizza are identified easily.
Other examples - a mixture of sand and sugar, oil and water, muddy water.