This concept is rather difficult, so I’ve attached a few movies!
As you watch the movies, remember negative feedback is much more common! When a stimulus keeps going in one direction, and your feedback system reverses the outcome. (like when your temp rises, you sweat... negative feedback)
The continuation of an original stimulus. This one is difficult to understand. The movie about hormones (which I attached) will be confusing, but if you watch it several times, you will get it! (the apple example)
The KHAN academy video is 5 min. After watching.. take this little quiz! (MAKE SURE YOU CAN PASS IT!)