Cell Membrane is the

• A. outer surface of cell; the semipermeable membrane surrounding the cytoplasm of a cell
• B. production department of the cell
• C. the basic unit of living matter
• D. colorless gel-like substance

Answer: (A)

The cell membrane is the outer boundary of the cell that encloses the cytoplasm and acts as a semipermeable barrier, controlling what enters and leaves the cell while helping maintain the internal environment and enable communication with the outside. This makes it the best match because it directly describes the membrane’s location and function.

The other descriptions refer to different concepts: a “production department” would imply a site of manufacturing inside the cell, which isn’t what the membrane is; the idea that the cell is the basic unit of living matter describes the cell as a whole, not the membrane; and a colorless gel-like substance describes the cytoplasm, which exists inside the membrane, not the membrane itself.