How the idea of cost is represented in a production possibilities curve?

In a production possibilities curve (PPC), the idea of cost is represented by the trade-offs between the production of two different goods. As resources are allocated to produce more of one good, the opportunity cost manifests as a decrease in the quantity of the other good produced, illustrating the concept of scarcity. The slope of the curve indicates the rate at which one good must be sacrificed to produce more of the other, highlighting the economic principle that resources are limited and choices must be made. Thus, the PPC visually captures the cost of forgoing one option in favor of another in production decisions.