Hey little buddy, as you grow up, your body goes through many changes, some visible and some not. One of the changes is aging, and there is a theory that explains why this happens called the "disposable soma theory of aging."
So, let me explain it to you in a way you can easily understand: imagine your body is like a car, and all the parts inside it are like the cells in your body.
Your body is made up of lots of cells that all work hard to keep you healthy, but these cells can only do so much work before they get old and start to break down. This is kind of like a car, where all the different parts can only work for so long before they wear out and need to be replaced.
In the disposable soma theory, scientists believe that our bodies are designed to focus on keeping us healthy and alive in the short-term, rather than in the long-term. So, our bodies prioritize making sure that we can survive and reproduce over making sure that we live to be really old.
This means that as we get older, our bodies start to spend less energy on repairing our cells and keeping us healthy, and more energy on just keeping us alive. This can lead to things like wrinkles, gray hair, and other signs of aging.
So, while it might seem like aging is just something that happens naturally, the disposable soma theory suggests that it's actually a result of our bodies prioritizing short-term survival over long-term health.