<span>Answer D is not correct, as gymnosprems are used widely for consumer goods such as lumber, soap, and nail polish.
Answer C is not correct event though wheat and corn are two of the main foods supplied to people in the world.
Answer B is a very subjective question, because some people argue that selective breeding helps agriculture, while others do not.
The correct answer is A. The green revolution was a period of scientific discoveries that lead to an increase in the supply of food worldwide.</span>
A ..................................................
I think it is liqid but i dont know realy.
The correct answer is option (d) They allow the exchange of gases between cells in the leaf and the external environment.
Stomata are the tiny openings present in the epidermis (outer layer of cells) of the leaf. They have a pore which is guarded by the guard cells which controls the opening and closing of the stomata. Air enters and exits through the stomata.
The main funtion of stomata is to facilitate the gaseous exchange. The gas exchange that occurs when the stomata are open helps in the process of photosynthesis. During photosynthesis, carbon dioxide is taken in from the atmosphere and oxygen is released as a by-product of photosynthesis. The glucose produced is converted into the starch and stored in the leaves.
Also, water vapour diffuses through the stomata into the atmosphere by a process called the transpiration.
Thus, stomata are the structures that are mainly involved in the gaseous exchange between the cells of the leaf and the atmosphere.
