A reason why the Civil War lasted four years is that the Union had to fully conquer the South.
Members of the House of Representatives serve two-year terms and are considered for reelection every even year. Senators<span> however, serve six-year terms and elections to the </span>Senate<span> are staggered over even years so that only about 1/3 of the </span>Senate<span> is up for reelection during any election.</span>
All of the above would be important factors .
The answer would be the amount of resources consumed during production.