Which structure is the rigid external layer found outside the cell membrane in plants, bacteria, or fungi?

• A. Cell Wall
• B. Vacuole
• C. Nucleus
• D. Cytoplasm

Answer: (A)

The rigid external layer outside the cell membrane in plants, bacteria, and fungi is the cell wall. It provides structural support and protection, helping the cell maintain shape and resist osmotic pressure. In plants it’s made of cellulose, in fungi it’s made of chitin, and in most bacteria it’s made of peptidoglycan. This layer sits just outside the plasma membrane and is typically porous, allowing water and small molecules to pass through. By contrast, the vacuole is an internal storage organelle, the nucleus houses genetic material, and the cytoplasm is the jelly-like fluid inside the cell membrane where many processes occur.