13. The growth of every kind of plant in a limited extent is another sign of the wisdom and power of Allah. For the generative power of every vegetable plant is so great that if free growth had been allowed to even one kind of plant, it would have covered the whole surface of the earth. But it is by the design of the All-Wise and All-Powerful Creator that every kind of vegetable is produced in a balanced measure. There is another aspect of the vegetable life. Each and every kind of it is allowed to grow only to a fixed size, height, and thickness, which is a proof of the fact that the Creator himself prescribed the structure, the shape, the size, the height, the leaves and branches, and the number of each and every plant, and no plant is allowed to go beyond any of these fixed limits.