I think you need to defeat darkrai at dark crater first. I'm not completely sure, though.
You can't. They just stay as they are like every other Pokemon in the game I'm afraid... However wouldn't it be cool if your partner could evolve...
Every Pokemon does not evolve. The legends, and unowns don't evolve. Only 90% of the Pokemon evolve.
Get a Pokemon Game Guide. They're big catalouges of every pokemon, where they are in every game, when they evolve, how they evolve, and how rare they are in each game.
Pokemon evolve differently every time.
yes. in all Pokemon games (or all the ones ive played) Pokemon evolve. But not every Pokemon evolves most do tho.
a new stage of what they were before
There is a Pokemon center in every mapped town in every Pokemon game except for the Rangers and Explorers.
In every Pokémon Mystery Dungeon game to date, you can only evolve Pokémon after beating the final boss. There's a cave in town that you gain access to after beating the game (you have to leave your partner behind and go alone), where if your Pokémon is a high enough level to evolve (lv 15 in your case), you can evolve it there.
Yes Togepi does evolve in Pokémon SoulSilver. It does evolve, but instead of evolving by levels, it evolves by happiness, which happens in every other Pokemon game with Togepi
It depends on which Pokemon it is because they all have different evolving levels.
it evolves by happiness in every game its in.
evolve sentret(lv 15) in every Pokemon