Which structural protein forms connective tissues? actin collagen keratin myosin

Collagen

Explanation:

Let us understand the role of each given protein.

a) Actin : It is a protein involved in muscle contraction and motility of cell. It is also important for cell division.

b) Collagen: as mentioned it is the protein present in connective tissues, which forms tendon. ligaments etc. It is the most abundant protein in our body.

c) Keratin : It makes hair, nails, claws, horns, hooves etc.

d) myosin : it is again a muscle protein, involved in muscle contraction etc.

your answer would be a. 12.5 kg