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Every pokemon, Hatched or Caught however does have IV's. These represent the pokemons inherent and unchanging aptitudes, Like why one pikachu is faster than another, and why one Kadabra is a little bit more Psychic than another.
Exactly what AnarchaArcana said. EV are when u battle other pokemon. Say you battle Roselia 4 times, that means when u level up it increases ur Special attack stat by 1 or 2 i think. I was battling the guy near Valor Lakefront that had 3 roselias. I battled him a ton of times with Macho Brace on and when i levelled up my Togekiss gained 8+ on its SP attack