Okay, Gerald Ford served 1 term from 1974 to 1977. John F. Kennedy served a partial term (because of his assassination) from 1961 to 1963. Richard Nixon served 1 full term as well as a partial second (because he resigned from office) from 1969 to 1974. Lyndon B Johnson served a partial term (because he was sworn in after Kennedy's assassination) and then a full term after that from 1963 to 1969.
So, you answer would be John F. Kennedy, Lyndon B. Johnson, Richard Nixon, then Gerald Ford.
Hope this helps!
More farm workers were needed because during the revolution bombs would destroy healthy crops that were being prepared for feasts. Hope I helped
The answer to your question is the Missouri Compromise.