Different materials have properties that are desirable or undesirable for use in an artifical joint.

Question

Desirable (D)l Undesirable (UD) l Not Revelant (NR)
1.Chemically Stable (D)
2.Atoms can roll over each other (NR)
3.Consists of long molecules (UD)
4.Tightly packed atoms or molecules (UD)
5.Electrons flow freely between atoms (D)
6.Loosely packed atoms or molecules (D)
7*Free electrons vibrate in contact with light (NR)

Is this correct?

Answer 1

3.Consists of long molecules . High density polymers are being successfully used already in joint.
I dont know what "roll over" means when applied to atoms, that is something I have never seen.