heart gold,soul silver, mystery dungeon and platinum i think that's it
No there is no way of transfering from Crystal to Emerald. Only RBY to GSC, and Emerald to all games beyond.
Yes, a psyduck does evolve in all Pokemon games! :)
i think you have to trade them from other games
no, you cannot get all the Pokemon in Emerald by the game alone. You can trade with other games to get the ones you need, or you can use a GameShark for the cheats.
For Emerald Version, you must get a ticket from a Nintendo Event to get Mew. For all other games, you must trade it from Emerald.
Yes, Pokemon Emerald is a real game. However, as with all games, 'fake' copies are sometimes sold by 3rd parties.
trade from other games
You have to do somthing with all three games.
With the appropriate codes, an Action Replay can get you any Pokemon that exist in your game and its predecessors (For instance, in Emerald you could get all the Pokemon in Emerald and the games before it)
level 20, as with all fossils in all games
yes,they are in all three gba games.
You can't without trading from other games or cheats.