I'm not sure, but weren't there Aliens on Mars not long ago that died out in early stages of Evolution because of their crappy planet?
Theoreticaly, Mars at one point could have supported life, but it has never been confirmed. On annother note, life is suprisingly resiliant.
Depends on how far into Evolution they are.
Not really. Evolution isn't a straight path from point A to point B. It would depend more on what they evolved to deal with.
I think it is highly likely that there are extra-terrestrial beings, given how big the universe is and everything. I find it hard to believe that out of every single planet and galaxy in the universe, which we haven't even scratched the surface of, there is not at least one alien species.
Exactly. Though if there is intelligent life out there, I don't see them coming to earth anytime soon.