Holly trees show an interesting adaptation in their leaves. In general, the closer to the ground a leaf grows, the more prickles it will have. The most probable reason is that it deters browsing by animals, and, because the leaves are prickly, the animals won’t be able to reach the leaves further up, so these can have a larger and more efficient (prickle-less) shape.
This investigation would fit either with the Plant topic in Year 3, or with the Living Things and Habitats topics of Year 4 and Year 6.
