Exocytosis: (A) Extrusion of cell bound vesicles, (B) Intrusion of liquid particles, (C) Instrusion of solid particles, (D) All of the above
Answer is A. In exocytosis, the intracellular content to be released into the ECF fuses to the cell membrane. Then it is packed in a vesicle formed by the cell membrane and is released to the ECF.