Answer: Stomata
Explanation:
Stomata are pores in the leaf that allow gas exchange where water vapor leaves the plant and carbon dioxide enters.
How day length affects crop production most plant donot grow when day length is less than 10 hours . Even if the temperature is kept within the optimum range _ For example in a climate _ controlled greenhouse _ most plant will just sit dormat until the magic 10 hours of light perday arrives
The answer to this question is option D