explain, using how an object’s motion changes over time, produces a straight line when the object is moving at a steady pace is different from an object that is moving at a pace that is increasing

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.