Answer:
the answer is food
Step-by-step explanation:
A primary reinforcer is a stimulus or reward that naturally satisfies a basic biological need or desire. It does not require any prior learning or conditioning to be considered reinforcing. Food is a classic example of a primary reinforcer because it is necessary for survival and is inherently rewarding to most living organisms. The satisfaction of hunger and the pleasure derived from consuming food make it a powerful motivator and a primary reinforcer.