21. Who Wants Some Beautiful Eggs
22. My Brother’s Cat Got Into The Fireplace
23. If Holly (Ilex Aquifolium) Finds Its Leaves Are Being Nibbled By Deer, It Switches Genes On To Make Them Spiky When They Regrow
So on taller holly trees, the upper leaves (which are out of reach) have smooth edges, while the lower leaves are prickly.