What is the difference between internal stimuli and external stimuli

Hey .

External Stimuli :External stimuli is a stimuli that causes a response from outside . E.g when it is cold ,  you keep yourself warm by putting a jacket .

Internal Stimuli : Causes a response from inside .  For example, when you eat a pizza, the urge to eat a pizza was triggered from inside. Either it was hunger or just your wish to go for pizza not a burger that was an internal stimuli.

For more understanding see the picture below .

Hope it help!

geologic time scale (for gradpoint) =)