Yes, Mewtwo can be caught in Cerulean Cave. As far as Mew is concerned, only hints about it's existence can be found in the Pokémon Mansion at Cinnabar Island. There is no way to catch Mew in Pokemon FireRed of LeafGreen. You have to trade it.
Mewtwo, yes, if you have a FireRed or LeafGreen with Mewtwo.
The legendary birds, Mew, and Mewtwo.
Mewtwo? Plus you cannot get Mew in Leafgreen or Firered.
There is no such thing as mewthree!!! only mewtwo and mew
I believe you get him by beating the Pokemon league with mewtwo in your party
Mewtwo, Deoxys, Ho-oh, Lugia, and Mew(I think).
You cant on Firered - sorry
haha mew 3 isnt a pokemon i reapeat is not real mew 3 is actual the newest version of mewtwo in fact i dont think you can even get mew or mewtwo but you can trade for a mew from pokemon x or y of firered of leafgrean or dark cry versions
no because there isn't a mew-three just mew and mew-two sorry
you can't Mew and Mewtwo are two completely different pokemon. Mewtwo is accually a clone of the original Mew. So... no, you can't evolve Mew into Mewtwo.
This is VERY debatable. Most say Mewtwo, Mew, Raikou, Entei, Suicune.
you don't. You can't find either Mew or Mewtwo in Emerald; you have to trade from FireRed or LeafGreen to get Mewtwo. You can't get Mew without an event or cheating.