Which of the following statements is correct about the cardiac muscles?
I. It is present in heart only
II. The plasma membranes of adjacent cardiac cells interlock at intercalated disc
III. The intercalated disc contains desmosome (adhering and gap junction)
IV. Gap junctions allow the cardiac cells to contract as a unit
(1) All are correct
(2) None of these
(3) II and IV only
(4) I and II only