When fighting in Vietnam, American soldiers

In 1637, colonists killed between 500 and 600 american indians in connecticut

Which events are correlated but do not necessarily have a causal relationship?

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