複選題5. Which of the following statements are CORRECT. (A) Fibronectin in extracellular matrix is a glycoprotein (B) Cytoskeleton-actin is located inside cell (C) Collagen in extracellular matrix is a glycoprotein (D) Integrin is located in lipid membrane. (E) Gap junction is the process that molecules and ions enter into cells through diffusion or active transport.