how go look for the legendaries!
Yes.
yes,you have to beat the Pokemon league 50 times to be able to go into space
u have to beat the Elite 4 then type in at Google " video for where to get rayquazza in Pokemon sapphire." that's it
If you are referring to the old GBA games, then yes and no. You have to beat the Pokemon League in Ruby and Sapphire to get Rayquaza but in Emerald you can get him before beating the Pokemon League. Hope this helped.
all you have to do is beat the Pokemon league 1 time its simple.
take the meteorite
You can get in after you beat Archie at the route 128 cavern.
you fill your pokedex
what do you mean the elite 4 are in the Pokemon league in evergrande city you should be able to beat them if you have good Pokemon
beat the Pokemon league.
After you beat the Pokemon league, you can train all your Pokemon, challenge the battle tower, do both, or start over.( i don't recommend starting over)
no to trade between leaf green and sapphire or ruby u must beat the Pokemon league then go to the seven islands and find the ruby and the sapphire gems to be able to trade