Here's why:
* No "duplication" glitch: FireRed doesn't have the common "duplication glitches" found in older Pokemon games like Red and Blue. These glitches exploited specific game mechanics to create extra copies of Pokemon.
* Trade Evolution: The only way to obtain multiple copies of Pokemon that need to evolve via trade (like Machop, Kadabra, etc.) is to trade them with another player.
What you *can* do:
* Breeding: You can breed Pokemon to get eggs that hatch into new Pokemon of the same species. This is the standard way to obtain multiple copies of Pokemon in FireRed.
* Trading with friends: You can trade Pokemon with friends to exchange different species and complete your Pokedex.
Let me know if you have any more questions about breeding or trading in FireRed!