As Primal Plasma enters the battlefield, it becomes your choice of a 3/3 creature, a 2/2 creature with flying, or a 1/6 creature with defender.
If an object enters the battlefield as a copy of Primal Plasma, it copies the values determined by its enters-the-battlefield replacement effect, but its power and toughness are determined by the copy’s own enters-the-battlefield replacement effect. This can cause you to have a 3/3 creature with flying, or a 1/6 creature with flying and defender, for example.
If an object on the battlefield becomes a copy of Primal Plasma, it copies the values determined by its enters-the-battlefield replacement effect.
While not on the battlefield, Primal Plasma is a 0/0 creature card. It doesn’t have flying or defender.