Read the following passage and answer the question that follow :
Today, bicycles are elegantly simple machines that are common around the world. Many people ride
bicycles for recreation, whereas others use them as a means of transportation. The first bicycle, called a
draisienne, was invented in Germany in 1818 by Baron Karl de Drais de Sauerbrun. Because it was made
of wood, the draisienne wasn’t very durable nor did it have pedals. Riders moved it by pushing their feet
against the ground.
In 1839, Kirkpatrick Macmillan, a Scottish blacksmith, invented a much better bicycle. Macmillan’s
machine had tyres with iron rims to keep them from getting worn down. He also used foot-operated
cranks, similar to pedals, so his bicycle could be ridden at a quick pace. It didn’t look much like the
modern bicycle, though, because its back wheel was substantially larger than its front wheel. Although
Macmillan’s bicycles could be ridden easily, they were never produced in large numbers.
In 1861, Frenchman Pierre Michaux and his brother Ernest invented a bicycle with an improved
crank mechanism. They called their bicycle a vélocipède, but most people called it a “bone shaker”
because of the jarring effect of the wood and iron frame. Despite the unflattering nickname, the vélocipède
was a hit. After a few years, the Michaux family was making hundreds of the machines annually,
mostly for fun-seeking young people.
Ten years later, James Starley, an English inventor, made several innovations that revolutionized
bicycle design. He made the front wheel many times larger than the back wheel, put a gear on the
pedals to make the bicycle more efficient, and lightened the wheels by using wire spokes. Although this
bicycle was much lighter and less tiring to ride, it was still clumsy, extremely top-heavy, and ridden
mostly for entertainment.
It wasn’t until 1874 that the first truly modern bicycle appeared on the scene. Invented by another
Englishman, H.J. Lawson, the safety bicycle would look familiar to today’s cyclists. The safety bicycle
had equal-sized wheels, which made it much less prone to toppling over. Lawson also attached a chain
to the pedals to drive the rear wheel. By 1893, the safety bicycle had been further improved with airfilled rubber tyres, a diamond-shaped frame, and easy braking. With the improvements provided by
Lawson, bicycles became extremely popular and useful for transportation. Today, they are built, used,
and enjoyed all over the world.
Read the following sentence from the fourth paragraph :
Ten years later, James Starley, an English inventor, made several innovations that revolutionized
bicycle design.
As it is used in the sentence, the underlined word revolutionized means :