1. "What was developed in 1869 to improve transportation across the continent?"

a. automobile
b. airplane
c. transcontinental railroad
d. steamboat

2. Who invented the first safe elevator?

a. Elisha Otis
b. Thomas Edison
c. Jonas Salk
d. Joseph Henry

3. What made car manufacturing easier for Henry Ford?

a. factory workers
b. assembly line
c. electric machines
d. metal parts

4. Jonas Salk created a vaccine for which disease?

a. chicken pox
b. small pox
c. polio
d. tuberculosis

5. In which city did Henry Ford start his company?

a. Detroit, Michigan
b. Chicago, Illinois
c. New York, New York
d. Omaha, Nebraska