Final answer:
The Production Possibilities Frontier (PPF) shows how much of two goods an economy can produce when using all available resources efficiently.
Step-by-step explanation:
The concept that shows how much of two goods an economy can produce when it is using all available resources as efficiently as possible is called the Production Possibilities Frontier (PPF). The PPF is a graphical representation of the maximum production levels of two goods that can be achieved given the available resources and technology. It shows the trade-off between producing one good and the other, highlighting the concept of opportunity cost.