The ending of the world in 2012?

there's 1 in a trillion chance that everything will be extinct (except the earth, of course). there are nations that are building underground bases before the so called ending of the world. people that would survive will have to bring lots of food with them, because once those asteroids hit the earth, every single species will die from the attack. the earth will go through several stages to recover from the blast, and it'll take millions of years until some other species show up.