29. Which of the following statements regarding cell-cell and cell-matrix adhesion is incorrect? 1. The major families of cell surface adhesion molecules include integrins. 2. Vertebrate gap junctions are composed of adherins. 3. A tight junction is made up of integrins. 4. NCAMs, a group of cell-adhesion proteins belonging to the Ig superfamily, bind to proteoglycans.
(A) 1 and 2
(B) 1 and 3
(C) 2 and 3
(D) None of above
(E) All of above