Alternating current electricity. This allowed electricity to flow further than Edison's first DC approach.
Railroads - allowed for transportation of materials to growing small cities, and large cities to become larger.
Antibiotics and antiviral medicines. - stopping deadly diseases and bacteria from spreading. This helped with many problems that would normally terminate 33% of populated areas that are infected.
Alternating current electricity. This allowed electricity to flow further than Edison's first DC approach.
Railroads - allowed for transportation of materials to growing small cities, and large cities to become larger.
Antibiotics and antiviral medicines. - stopping deadly diseases and bacteria from spreading. This helped with many problems that would normally terminate 33% of populated areas that are infected.