All living things have a certain span of life. In the same way, human beings have a limited life. When the life of a person is about to end he has less energy and strength. The body naturally slows down after a lifetime of work. Hearing and eyesight may get worse, and other several problems of heart and lungs would arise and other parts of the body do not work as well as in youth. The body naturally wears out. However there are some exemptions, people who had good health throughout the life often remain very active in old age. For example, a flower starts as a bud, then blossoms, and then wilts and dies.