Answer:
A. Tight junction
Explanation:
Tight junctions are cell junctions that form a water-tight seal between adjacent epithelial cells. They are composed of transmembrane proteins that join the outer layers of the plasma membranes of adjacent cells together. This seal prevents the passage of substances between the cells, forcing them to move through the cells instead. This helps maintain the integrity and barrier function of epithelial tissues, such as the lining of the intestines or the blood-brain barrier.
