Both erythrocytes and bus/taxi drivers' main job is to transport important components. Erythrocytes transport oxygen and carbon dioxide through the body. Likewise, taxi/bus drivers carry citizens through the city. Citizens are important to the city just as oxygen is important to the body. Taxi drivers move through, and reach all parts of the city; similar to how erythrocytes transport oxygen all throughout the body. In addition, there are great amounts of both Erythrocytes in the body and taxi/bus drivers in the city.
