It's in Viridian City, the place where you get Professer Oak's package.
in gym durr
Head to fuchsia city for your next badge.
8th gym badge the water badge
its very simple trade to fire red and back to leaf green if that doesn't work you have to get every gym badge.
you can't get mamoswine in Pokemon leaf green because it doesn't exist in leaf green
It is your rival from Pokemon fire red and leaf green versions.
in gym durr
Give the hm or TM to your Pokemon
Head to fuchsia city for your next badge.
beat the gym leader
I get my 8th badge in Sootopolis gym.
In fire red/leaf green it is in Cerulean City in sapphire/ruby/emrald it is in Mauville City
Simply beat Giovanni in Viridian City and get the Earthbadge: it makes all Pokemon obey you.ORAll Pokemon obey you, the badges are for Pokemon traded from other games.
leaf
8th gym badge the water badge
In generation I, II, III, IV (Red, Blue, Green, Yellow, Gold, Silver, Crystal, Fire Red, Leaf Green, Heart Gold, Soul Silver) you obtain the Thunder Badge in Vermillion City. South of Cerulean City.
The green part of the leaf is green because of the chlorophyll inside