beat it again. nothing will happen
We can get other regions starter Pokemon if we defeat the battle tower
No it's already unlocked. You can even go in there before going in any other buildings at the battle frontier.
At the fight area (after you beat the Pokemon league)
Nothing
Nothing.
Yes.
there is no battle frontier in Pokemon pearl,but there is a battle tower. you can go there after you beat the elite 4
you cannot ever beat the battle tower. but if you have completed the sinnoh pokedex then the battle tower will help you complete it. you can battle at the battle tower as long as you want.
to get bp (battle points) you have to beat people in the battle tower.
after you beat your rival at battle tower he will reappear every so often
you have to go to the battle fronteir after you beat the game
collect all the Pokemon in the national pokedex