You catch regirock at the desert near maulvil town.you catch registeel west of the safari zone.
You have to get either Pokemon Emerald, Sapphire or Ruby for GBA. You could get the special movie event Regigigas, which gives you a chance to get all three.
there are three that you can CATCH in pokemon emerald its Groudon, Kyogre, and rayquaza regice registeal regirock litos lotias
You cannot catch it in platinum but only in ruby, sapphire and emerald.
no you do not just the Pokemon relicanth and wailord.
cindaquil must be migrated from emerald version... in emerald, once you catch all the pokemon, the professor offers you one of three pokemon... you may pick from the johto starters (cindaquil, chikorita, and totodile)
It will only fight you if you have the three Reggis Pokemon from previous games
For Pokemon ruby you can catch the three regis, rayquaza, groudon, and latios/latias. In sapphire you can catch the three regis, rayquaza, kyogre, and latios/latias. However, in emerald you can catch kyogre, groudon, rayquaza, the three regis, and latios/latias.
All 3 must be traded from either ruby, sapphire or emerald.
You can't catch wild Treeko in Pokemon Emerald. You need to choose it out of the three Starter Pokemon that are offered to you at the beginning of the game: Treeko, Torchic, and Mudkip. to see it, battle rival or other trainer
To get a Totodile in FireRed you must trade it over from Emerald version. To get the Totodile in Emerald you must first complete the Hoenn PokeDex and you will be given a choice of three Pokemon: Totodile, Cindiquil and Chikorita.
Silverpowder can be obtained three ways, One catch a lot of bug type Pokemon like venonat, Two get the silverpowder from the shadow venomoth in Pokemon xd gale of darkness, Three get one from Pokemon emerald.
The three legendary Pokemon in Pokemon emerald is Kyorge, Groundon and Rayquazer.