Yes you do. You will need to trade for Surskit/Masquerain, Meditite/Medicham, Roselia, Zangoose, and Lunatone.
If you want to fill your pokedex, you must trade between Ruby and Emerald to gain the Pokemon that are not in Sapphire.
you have to fill up your pokedex
you can trade someone who has chickorita or migrate one from emerald if you got one in emerald if you completed the pokedex the profesor will let you choose one out of the three second generation beginner Pokemon
Just catch the most Pokemon you can ;)
There are many different ways to fill the national Pokedex. You can play FireRed, Leaf Green, Sapphire, Ruby and Emerald and transfer the Pokemon via Pal Park. Use the global link to trade for the missing Pokemon or trade with friends.
To get a cyndaquil u must trade one from Pokemon emerald or Pokemon xd gale of darkness or breed the purified quilava from Pokemon colosseum
You have to fill the pokedex, then go to prof. Britch.(He is in the first town)But i am not sure...
trade-transfer and repeat
fill the pokedex then go to the hotel in lilycove. then talk to the programmer.
You have to battle every single trainer if not true improve answer
link trade a haunter and it will evolve
fill out your main pokedex. Then i think you go back to the professor but i may be wrong.