Cell wall in:

**The reasoning** Cell walls are **rigid, protective structures** found outside the cell membrane. Plants need them for: - **Structural support** — to stand upright without a skeleton - **Protection** — against pathogens and physical stress - **Shape maintenance** — plant cells stay firm and boxed The cell wall is made of **cellulose** (a tough carbohydrate). Animals don't have this because we have skeletons for support and need our cells to be **flexible** for movement — imagine if your muscle cells were boxed in rigid walls! **Why the wrong options tempt you** - **A (Animal)** — You might confuse cell wall with cell *membrane*, which both plants AND animals have. But the membrane is thin and flexible; the wall is thick and rigid. - **C (Both)** — Tricky! Both have membranes, but only plants have walls. - **D (Neither)** — This contradicts basic biology — plants definitely have cell walls. **Quick takeaway** **Plants = Cell Wall + Membrane** (for strength and structure); **Animals = Membrane only** (for flexibility). Think: "Plants stand, animals move — cell walls vs. no walls."