Question

why more number of stomata is seen under the leaves

Answer 1

To reduce exposure, stomata are found on the underside of the leaves. They are protected from the sun as excessive heat can increase the rate of water vapor leaving and thus wither the plant. Stomata also have guard cells around the epidermis that close when too much water is being lost.

Answer 2

here is your answer

because The exchange of oxygen and carbon dioxide in the leaf, as well as the loss of water vapor, occurs through pores called stomata (singular = stoma). ... The number of stomata on leaf surfaces varies widely among different species of plants. The lower epidermis of the leaf tends to have a higher total than the upper surface.

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