Which of the following statements about the molecular arrangement of actin and myosin in myofibrils is false? (1) Each actin is made of 2F actins (2) F-actin is the polymer of G actin (3) 2F-actins are twisted into a helix (4) Two strands of tropomyosin lie in the grooves of F-actin (5) Troponin molecules are distributed at regular intervals on the tropomyosin (6) Troponin forms the head of the myosin molecule (7) The myosin is a polymerised protein