Answer:
It's C.
Explanation:
It's not Muscles because muscles are tissues made up of specialized elongated cells or fibres which can contract(shorten or thicken) to bring about movements. And we all know Ca and Proteins are needed for the formation of strong and healthy bones, muscles and teeth. Same goes for ligaments.
For polypeptide chains, its a vital part involved in the breaking down of Proteins.
Proteins->Proteoses->Peotones->Polypeptide-> amino acids.
PeAcE.
