When a human begins life we all start as an infant and eventually a child, as a child life is simplified and there is much that will be learned. As we start aging we all get smarter, wiser, and act mature, parts in the human shape start changing, and that just affects the human appearance.  As humans, we enlarge and change, Adults are the main change in life.  Adults have learned, studied, and are fully aware the queries and answers that are usually asked in life. Life is change because the details and facts that we familiarize as we age and the small changes in the human apperance.