Which major even most contributed to the spread of islam?

Which event was one of the causes of the french revolution in 1830?

Which statement is an example of direct democracy? a) people elect a senator to the u.s. congress. b) the town council approves funding for a new high school. c) the president issues an executive preventing states from executing prisoners. d) voters approve an amendment allowing elderly people to pay nothing in property tax.

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