1.When do national elections take place?   
 2.Every four years the president, vice president, _____________________, and __________________ are up for election (on-year elections).       
3.On even-numbered years when there isn’t a presidential election, _____________________  and_____________________ are included in the election (off-year elections).   
4.What happens if a vacancy occurs due to a Senator’s death, resignation, or expulsion?