Which event increased interest in a railroad route to California?

Discovery of gold
Opening the Erie Canal
Improvement of the lock system
Joining the First Transcontinental Railroad

Which answer best explains the overall impact of the chicken on native american populations in the new world? negative; it destroyed much needed grain crops neutral; it was not well adopted by native americans insignificant; other animals were more quickly accepted positive; it brought a good source of protein to the native american diet

When conducting research for forming a hypothesis, which practice should historians follow?

What development led the soviet union to establish the warsaw pact? the soviets gained control over satellite countries. west germany joined nato. the allied powers grew weaker. the berlin wall was erected between east and west germ