Nitrogen in the is not in a form that plants can use.
1.water
2.soil
3.atmosphere
4.none of the above

The correct copper is important in the synthesis of collagen.   
Copper activates an enzyme called lysyl oxidase that's required for collagen maturation.Lysyl oxidase catalyzes the formation of aldehydes from lysine residues in collagen and this results in cross-linking collagen (stabilization of collagen fibrils).