This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cailage tissue & cell junctions, Subject name: Anatomy
Which one of the following statements about the gap junction is true? 
Select and explain. 
A. It extends as a zone around the apical perimeter of adjacent cells., B. It possesses dense plaques composed in pa of desmoplakins., C. It permits the passage of ions from one cell to an adjacent cell., D. Its adhesion is dependent upon calcium ions.
C: It permits the passage of ions from one cell to an adjacent cell.
Answer: C: It permits the passage of ions from one cell to an adjacent cell. 
Explanation: The gap junction channel regulates the passage of ions and small molecules from cell to cell, excluding those having a molecular weight greater than 1200 Da. The tight junction is the zone of adhesion around the apical perimeter of adjacent cells. The other statements are characteristics of desmosomes.