After you get the 4th badge go to petalburg city and enter the gym go through it then fight Norman for your 5th badge.
from the fight area to the survival area and you may also migrate from ruby sapphire emerald migrate is to put Pokemon ruby sapphire emerald instead of the cover but you must put 6 Pokemon in the PC in ruby sapphire emerald then select in Pokemon platinum migrate from ruby or sapphire or emelard
You must either get a masterball from team aqua base or game corner. Then you must fight a legendary and throw the masterball right away.
In Pokemon Sapphire, Militank is a cow Pokemon that gives milk. You must trade another player one of your other Pokemon for it.
If you want to fill your pokedex, you must trade between Ruby and Emerald to gain the Pokemon that are not in Sapphire.
Seedot can't be caught in the wild in Pokemon Sapphire. You must trade it from Ruby or Emerald.
Latios is not catchable in Sapphire you must get one from Ruby or Emerald.
You cannot. You must trade it from Pokemon Sapphire
It must be imported from Pokemon Ruby/Sapphire/Emerald.
You can get Charmander in Pokemon Sapphire by obtaining it in Pokemon FireRed or LeafGreen and trading it to Sapphire. To have Charmander registered in the Sapphire PokeDex, you must defeat the Elite Four. You may have the Charmander before that, but it won't register in the PokeDex.
Zangoose does not appear in Pokemon sapphire, but you CAN get it. To get it, you must trade Pokemon with your friend if your friend has Pokemon ruby which is the only game you can get zangoose in. Or you can just buy Pokemon ruby.
You cannot catch Mawhile in Sapphire. You must trade it from Ruby/Emerald.
You must evolve Feebas.