2006-12-03 22:34:58 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Botany
1. Their broad, flat shape offers a large surface area for absorbsion of sunlight and carbon dioxide.
2. Most leaves are thin and the carbon dioxide has to diffuse across short distances to reach the inner cells.
3. The large spaces between cells inside the leaf provide an easy passage through which carbon dioxide can diffuse.
4. There are many stomata in the lower surface of the leaf. These allow the exchange of carbon dioxide and oxygen with the air outside.
5. There are more chloroplasts in the upper(pallisade) cells than in the lower(spongy mesophyll) cells. The pallisade cells, being on the upper surface, will receive most sunlight and this will reach the chloroplasts without being absorbed by too many cell walls.
6. The branching network of veins provides a good water supply to the photosynthesizing cells. No cell is very far from a water-conducting vessel in one of these veins.
2006-12-03 22:59:52 · answer #1 · answered by polol 2 · 0⤊ 0⤋
Leaf is dorsiventrally flattened structure which contains Chlorophyll as pigment so as to perform photosynthesis. Leaf consists of midrib, veins & veinlets which help to keep leaf in flattened manner so that Sunlight is sufficiently available for photosynthesis.
2006-12-04 13:28:16 · answer #2 · answered by Sharada B 3 · 0⤊ 0⤋
the same why we humans learn how to digest food and all the carnevorous know why they eat meat Allah teaches them
2006-12-04 06:52:05 · answer #3 · answered by pervaiz elahi bukh soomro 1 · 0⤊ 0⤋