Here's a breakdown:

* Stimulus: Anything in the environment that causes a reaction in an organism. This could be a physical change, a chemical change, or even a change in light, sound, or temperature.

* Response: The reaction of the organism to the stimulus. This can be a change in behavior, physiology, or even growth.

Examples of Stimuli and Responses:

* Stimulus: A bright light.

* Response: A plant bending towards the light.

* Stimulus: The smell of food.

* Response: An animal salivating or moving towards the food.

* Stimulus: A change in temperature.

* Response: A mammal shivering to stay warm or sweating to cool down.

Let me know if you have any other questions!