Answer: Resources
Explanation: The production possibility model is used by the economist to evaluate the relationship between scarcity and resources. The basic assumption while preparing a PPM is that the time frame and resources for production such as capital, land and labor are fixed.
The PPM shows the production possibilities in an economy using only two goods. One of which is shown in X axis and one in Y axis. It helps to calculate the quantity of two goods that are to be produced with limited resources, resulting in maximum output to the economy.
