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 a security guard controlling access to a building. The cytoplasm is the jelly - like substance inside the cell, the endoplasmic reticulum is involved in protein and lipid synthesis, and the mitochondrion is the powerhouse of the cell.

Answer:

A. cell membrane