What are three constitutional safeguards against abuse of presidenttial powers?

Read carefully about Presidential Powers.

http://docs.google.com/gview?a=v&q=cache:opzdyfcKr7wJ:www2.hoover.k12.al.us/schools/hhs/faculty/kself/USGOV/Documents/Executive%2520Branch/roles%2520of%2520president%2520summary.pdf+constitutional+safeguards+against+abuse+of+presidential+powers&hl=en&sig=AFQjCNF0E5OG-0WAKO7Sulaax12F6RfcEw