Animal cells lack which of these found in plant cells?

**The reasoning** Think of the cell wall as a **rigid protective box** made of cellulose that surrounds plant cells, giving them their fixed, rectangular shape. It's what makes plants stand upright and provides structural support. Animal cells don't have this rigid wall — they only have a flexible **cell membrane** (which both plant and animal cells possess). This is why animal cells are more rounded and can change shape, while plant cells look boxy under a microscope. The principle: **Structural differences reflect function**. Plants need rigidity to stand tall; animals need flexibility to move. **Why the wrong options tempt you** - **A (Nucleus)** and **C (Cytoplasm)** and **D (Mitochondrion)** — These are in BOTH plant and animal cells. The nucleus controls the cell, cytoplasm is the jelly-like filling, and mitochondria produce energy. Don't confuse "animal cells lack" with "both cells have." The trap: assuming animal cells are somehow "less equipped" when they actually share most organelles with plants. **Quick takeaway** Remember: **Cell WALL = Plants ONLY** (for structure); the flexible cell membrane is what animals use instead, allowing them to move freely.