 Some changes over which we have no control are called uncontrollable changes. So for example, the formation of clouds or the phases of the moon. We do not have any control over these changes, right? Or the coming of a storm. These are uncontrollable changes. But there are some changes over which we can have control and those are called control changes. So for example, if you're going to visit your friend on a cycle, you can speed up you can slow down. You can change. You have that control over the speed of the bicycle. This is an example of a control change. Also, if you want to protect anything made out of iron, we tend to apply a layer of zinc on top of it so that it does not rust. This is again a control change. We can control the rusting of iron. We can delay it by a long long way by just by just trying to protect it by by adding a layer on top of iron. Usually zinc, adding a layer of zinc on top of iron so that it does not rust. This is a control change. We can exert. We can have some control over it.