Question

In plants, exchange of gases takes place through
A) Stomata
B) Palisade tissue
C) Spongy tissue
D) Mid-rib

Answer 1

Hint:In order to carry out the process of photosynthesis, the green plants require carbon dioxide as a means to deposit oxygen. While to carry out their respiration, they need oxygen as a means for disposing off the carbon dioxide.

Complete answer:
>Option A: Stomata are defined as the tiny openings or pores present within the plant tissues which are necessary for gaseous exchange. These are typically found in plant leaves but can even be present in some stems.The stomata are surrounded by specialized cells or the guard cells that facilitates the opening and closing of the stomatal pores. These pores facilitate the plants in gaseous exchange. Therefore, this is the correct option.
>Option B: Palisade tissue is a type of an assimilative parenchymatous tissue mostly found in the leaves and to some extent in the stem. This tissue comprises compactly arranged thin walled cells standing close to each other with their long axis perpendicular to the leaf or the stem surface. Therefore, this is the incorrect option.
>Option C: Spongy tissue is tissue present both in the plants and animals. In plants, it functions as a part of the mesophyll forming a layer close to the palisade cells present within the leaf. Therefore, this is the incorrect option.
>Option D: Mid-rib is defined as the central, thick and linear structure running along the length of the plant lamina or the plant thallus. This organ is meant for providing support to the plant. Therefore, this is the incorrect option.
Thus, the correct Option is (A) stomata.
Note:The net gaseous exchange from the leaf surface depends on the intensity of the light incident on it. Majority of the stomata is present on the underside of the leaf in the form of pores, and helps in transportation of water..