The production possibilities curve illustrates the basic principle that

If all the resources of an economy are fully used, more of one item could be produced only if less of another item is produced

Explanation:

The concept of production possibility curve shows the different commodities that can be produced in a given economy, given the prevailing level of technology, if all available resources are efficiently utilized. The idea behind production possibility curve is that in other for in order to produce a particular commodity, the production of another commodity has to be scarified provided that i. e if all the resources of an economy are fully used, more of one item could be produced only if less of another item is produced