In most cases, the relationships the team found were 14) __________.
By contrast, a leaf's 15) __________ is unrelated to the sizes of the cells inside. This allows plants to produce leaves with a huge range of surface areas without the need for larger cells, which would be 16) __________, the researchers said. Variation in the number of cells arranged vertically cannot be large because light can penetrate only so many layers of cells. On the other hand, the number of cells arranged horizontally in