It can, it never happened and it's very unlikely to happen.
The producer(s) of the movie.
No. In 1982 it was nominated, but Gandhi actually won. (The other nominees were Tootsie, Missing and The Verdict).
Anything is possible. While "No Country For Old Men" is the front-runner, there could be an upset on Oscar night. "Atonement" has won the BAFTA and the Golden Globe for Best Picture, so it could...
No. The Academy Award for Best Picture of 2010 went to "The King's Speech."