Answer
Shelf-shading is promoted by the fact that vascular plants grow upward, so upper leaves can sit above and shade lower leaves. The fact that leaves are arranged in patterns (phyllotaxis) means that they can be arranged in space to minimize this self-shading.
Work Step by Step
Review concept 36.1 and make a list of features which could place one leaf above another and ones which could help spread leaves to minimize the effects of this.