LEAF, DRAWING

Leaf blade or lamina.
Illustration showing a section of leaf blade (transverse cross-section), showing the leaf surface and stomata (pores), the mesophyll (middle layer of yellow chloroplast-filled cells), and a vein (dark green tube).
Carbon dioxide enters the leaf through the stomata and oxygen is expelled through the same stomata after photosynthesis has taken place.
Water, which is absorbed by the plant at the roots, is carried to the leaf through the veins.