Many years ago an associate of mine shared something with me that has stayed with me ever since. What she shared was her meaning of the word responsible. She said you can break it down into its two parts, respond and able. When you are responsible you are able to respond.
The word react, she pointed out, can also be broken down into its two parts, re and act. The prefix re means again, or back, or backward, as in revert, to turn back. The root act means to do or to perform. The word react therefore means to take an action against or in opposition to that which has occurred or against that which was done to you. It also means doing something back to the person who did or said something to you. Someone says something mean to you, you react, you act back, you say something mean back to them. One child hits another child, the second child reacts, and strikes back at the first child.
React is what an animal does when it acts instinctively. There is no thought process in an instinctive action. Nor is there any thought process in a reaction. A reaction is what happens in a chemistry project; when I mix together two chemicals I get a reaction.
When we respond, however, we act responsibly, we consider our response to some action by another. There are so many things we can consider. We can consider the mental state of the doer, the truth of the words that may have been said about us, we can consider the relationship we have with this person, and we consider how important what occurred is.
Being able to make this extra step, this consideration, is what separates us from other animals. It is what gives us power over all the other animals on our planet.
To respond is powerful; to react is powerless.