Which of the following is NOT a factor shown on a production possibilities curve?

A production possibilities curve (PPC) illustrates the maximum output combinations of two goods that can be produced, given a fixed amount of resources. It effectively showcases several important concepts in economics.

Resource allocation efficiency is demonstrated along the curve itself, where points on the curve indicate efficient use of resources. If resources are not allocated efficiently, the economy is producing inside the curve, showing inefficiency.

The concept of trade-offs is central to the PPC. It visually represents the trade-offs between producing one good versus another; moving from one point on the curve to another requires a reallocation of resources from one good to another.

Opportunity cost is integral to the PPC, as the curve illustrates the cost of forgoing the next best alternative when choosing to produce more of one good over another. The slope of the curve indicates the opportunity cost of shifting resources from one good to another.

However, preference changes over time do not directly relate to the production possibilities curve itself. The PPC assumes a set of preferences and technology at a given point in time. While consumer preferences can influence what is produced in the long run, they are not a factor depicted on the curve itself, which focuses on resource capabilities and trade-offs, rather than changing preferences.