Answer:
Sacrificial protection is basically attaching a piece of metal that is more reactive that iron to the object made of iron. This more reactive metal, commonly magnesium or zinc, will corrode in the place of iron. That is, the more reactive metal will feed the iron with electrons each time the iron is oxidised to form iron ions, thus reverting it to iron once again instead of letting it become iron hydroxide (rust). Thus, the more reactive metal is sacrificed for the iron.