Why did people emigrate durning the great migration

Marine exptoration of oil uses seismic waves to locate oil in the seabed. what is a negative impact from seismic waves on the aquatic ecosystem of the ocean? a. seismic waves kill microoganisms b. seismic waves disrupts the sand and causes seafloor erosion c. seismic waves have virtually no adverse affects on marine life d. seismic waves damage the sonar that dolphins and whales use to orient themselves underwater

In italy, the distance between milan in the north and palermo, sicily, in the south is about 550 miles. in the united states, the distance betweenboston, massachusetts, and savannah, georgia, is about 900 miles. do you think the american revolutionaries of 1776 in the 13 colonies faced some of the same challenges as the patriots who struggled for italian unity in the 1860s?  

Why was the treaty of versailles harsh on germany?