The stimulus is known to be the change in the environment, whether it is external or internal. There are instances when the stimulus can be food. For example, whenever you smell something inside your home that smells good, it can be enough to make you feel excited. The response will refer to the kind of reaction that you will provide after you have been exposed to the stimulus.
Let us say that you have smelled food. The food is something that you like. You cannot help but feel that your stomach will start to grumble because you are hungry, or you would like to eat immediately because you are already excited to taste the food in your mouth.