400
                                Which of the inventions from this chapter, such as the car, the telegraph, the light bulb, or the polio vaccine, do you think is most important?  Why?
                                For example:
I think that the car in the most important.  Without the invention of the car, we wouldn't have a fast and safe way to get from place to place.
OR  I think that the polio vaccine is the most important.  Many more people would have died from the disease.