* Organism: A complete living being, made up of multiple organ systems working together. Examples: a human, a tree, a bacterium.
* Organ: A structure made of different tissues that work together to perform a specific function. Examples: the heart, the lungs, the stomach.
Think of it like this:
* Organism: The whole house.
* Organ: A room in the house.
The house (organism) contains many rooms (organs) that work together to make the house function.
