Many years ago, doctors trained nurses to help them treat people. Today, nurses go to school to learn about medicine and about how to help people when they are sick. Nurses perform many of the same duties as doctors.
The first teachers in the United States were students who did well in school and were hired to teach other students. Today, teachers must have college degrees to teach. Schools today are larger than those in the past and often have several separate classes at the same grade level.
Firefighters are community heroes and their job is to help wherever there is trouble. Firefighters must be well trained, wear protective uniforms, and ride on trucks that are equipped to fight fires. Firefighters and the equipment they use today have changed significantly over the years.
Doctors help people stay healthy. When people get sick, doctors help them get well again. Today, doctors use many complex instruments to treat people. Long ago, doctors had few instruments and did not know as many ways to help people get well.