Population matters because it affects how many people there are in a place and in the world. More people means more things need to be taken care of, such as making sure everyone has enough food and a place to live. Good doctors and teachers are also needed to help people be healthy and learn new things. With more people, governments and other organizations need to make sure they have enough supplies and resources to help them. By understanding how population affects things around us, people can make better decisions to make sure everyone is taken care of.