Have you seen a picture puzzle where you have to arrange different pieces of the puzzle together to form a bigger picture? Similar to that, reductionism is a way of thinking where you take a complex problem and break it into smaller pieces to understand it better.
Let's say you want to understand how a car moves. You can break it down to smaller steps- how the engine works, how the wheels rotate, how the fuel is burned, etc. This way, by understanding individual steps, you can understand how a car moves.
Reductionism is used in many areas of science, like medicine, chemistry, and physics. It helps scientists to understand complex problems by breaking them into smaller, easier-to-understand issues.
However, reductionism also has its limits. Sometimes, breaking down a bigger problem into smaller pieces can make it difficult to integrate the pieces and understand a situation as a whole. For example, understanding human behavior by just studying single brain cells or hormones is reductionist because it doesn't show how all the parts work together to create a personality or human emotion.