AP BIOLOGY

Detailed explanation-1: -Lower surfaces are not directly exposed to sun. This tends to reduce excessive water loss. It is a beneficial adaptation to check water loss in plants. Thus, the underside of leaves have more stomata.

Detailed explanation-2: -Stomata are generally more numerous on the underside of leaves. They provide for the exchange of gases between the outside air and the branched system of interconnecting air canals within the leaf.

Detailed explanation-3: -If more stomatal pores are present on the upper side, due to high rate of evaporation from the upper epidermal layer, the water present in the plant gets evaporated and the amount of water in plants get reduced. So in order to prevent this, more stomata are present in the lower epidermis than in the upper epidermis. Q.

Detailed explanation-4: -Stomata are found mainly on the lower surface of the leaf to reduce water loss by transpiration.

Detailed explanation-5: -Generally lower surface of the leaf has more number of stomata, especially in dicotyledons.