What were the reasons behind the start of the crusades? And who called of it​

Which physical feature minimizes population density in northern africa?

What new concept did the the american revolution introduce into the world

The major impact third parties have on presidential elections has been to.. a. encourage larger vote turnout b. recruiter leader from the democratic and republican party to run for president c. generate increased party identification among the electorate d. developing issues that are later adopted by the major political parties e. drawn off of votes from the major parties to throw election into the house representatives