Read this excerpt from Chapter 1 of Wheels of Change by Sue Macy. Solid rubber tires and pedals replaced metal ones. Frames were

made of steel instead of iron or wood. Seat springs were improved and brakes were added. The weight was reduced to 50 and then 40 pounds. Each of these changes distanced the velocipede from its origins as a machine for the "swift of foot" until finally, a new term became popular for the two-wheeled wonder: bicycle. Which of these were solutions that improved the velocipede? eliminating metal tires enhancing the construction of seats strengthening wooden frames adding iron for weight adding brakes