What does iron and calcium or carbos do?

Question

like take drifblim for example it has low defence if I give it an iron like 20 times or 10
will it have more defences than usual?

Answer 1

Drifblim's Defense will raise. You can only use 10 before they stop working for that stat.

Carbos = Speed
Iron= Defense
Calcium= Sp.Attack
Zinc= Sp. Defense
Protein= Attack

They will each add 10 EVs for each use.

1st use +2
2nd +3
And the pattern goes back and forth.

Answer 2

This will have what you need to know. http://Pokemondb.net/ev