Can senators be re-elected?
yes there is no term limit for senators
What are the reasons why incumbent senators are less likely to be reelected than incumbent representatives?
Each of the 435 members of the House of Representatives serves a two-year term. The 100 Senators six-year terms. However, the majority of incumbent congressmen are often reelected to multiple terms. Since members of the House serve two-year terms, it can be said that Congress is reelected every 2 years.