you dont
in this game and ruby and Sapphire Scott shows no sign of Pokemon what so ever.
Scott is a scout that watches good trainers.
you cant unfortunatly
Its a berry given by Scott in Pokemon emerald.
In a small house at the battle frontier
OK, in emerald, Battle Tower is a part of the Battle Frontier. You can access it by beating the elite four. Scott takes you there.
its not an emerald its RAYQUAZA the main legendary Pokemon in Pokemon emerald.
Talk to Scott to receive a special berry.
You cannot get a Yanma in Pokemon Emerald, as only Hoenn Region Pokemon can be found in Pokemon Emerald.
If you speak to Scott (the manager of the Battle Frontier) he will reward you with exclusive Berries.
You never fight Scott. You only battle the frontier brains to get BP to spend learning new moves or buying items.