It took 10 years to build the panama canal :)
Option 'B' = changes in climate, had the greatest impact on pre-historic man.
Changes on the weather forced men to move periodically or cyclically, usually returning to their original location at various times. When they moved to colder climates, they would make clothing out of animal skins, to protect themselves. When the nomads learned how to plant, they didn't need to search for other places anymore.
Answer:
California already had a large unemployed population--most of them recent migrants from the 1920s. ... Most of the first migrants to arrive in California were from Oklahoma.
The Declaration of Independence drafted by Thomas Jefferson.
