Identify the common type of cheese that is often shaped into small, round pieces and commonly used as a topping on pizzas. <nis:link nis:type=tag nis:id=QuizTime nis:value=QuizTime nis:enabled=true nis:link/> <nis:link nis:type=tag nis:id=quizz nis:value=quizz nis:enabled=true nis:link/>