Question

which organelle can be compared to a security guard who decides whom may enter a building and whom may not? cell membrane cytoplasm endoplasmic reticulum mitochondrion

Explanation:

The cell membrane controls the movement of substances in and out of the cell, similar to how a security guard decides who can enter and leave a building. Mitochondria are the power - houses of the cell, endoplasmic reticulum is involved in protein and lipid synthesis, and cytoplasm is the jelly - like substance within the cell.

Answer:

cell membrane