The gas most commonly associated with plant respiration is carbon dioxide (CO2). Although plants primarily utilize carbon dioxide during photosynthesis to convert light energy into chemical energy, they also engage in respiration, a process that occurs in all live cells. During respiration, plants consume oxygen and release carbon dioxide, thereby producing energy required for their growth and metabolic functions. This process occurs mainly at night when photosynthesis cannot take place due to the absence of sunlight. Thus, carbon dioxide plays a dual role: as a raw material in photosynthesis and a waste product in respiration.