Need some important information

Hi guys, if I download MoP, can I go defeat the lich king if I want do some past extension too or it's just MoP?

Thx!

Yeah, you can pretty much solo all previous expansion content, but you'll need to find a buddy to do some with, as the mechanics of certain raids and/or instances require more than 1 player in order to complete. (Such as Ulduar last boss).
Have fun, my dude.

Thx buddy !! :D