What was the main cause of the surge in California's population between 1840 and 1860? A) the availability of cheap farmland

B) the migration of freed slaves

C) the discovery of gold

D) the arrival of immigrants from China

Which were the most important issues during the presidential election of 2008? a.economic downturn and environmental protection b.two overseas wars and economic downturn c.two overseas wars and campaign spending d.environmental protection and campaign spending