Cellular respiration is broadly divided into two stages, the first stage is called glycolysis and the second stage is the Krebs cycle or TCA cycle. Glycolysis occurs in the cytoplasm of the cell in which one molecule of glucose is broken down into two molecules of pyruvic acid and a small amount of energy. Krebs cycle occurs in mitochondria, further breakdown of the respiratory intermediate is done to produces a large amount of energy. In the given question, an area marked X represents a common feature of both the stages of respiration which is ‘energy is released’ in both stage one and stage two.
Respiration is a process in which energy is released due to the breakdown of glucose molecules with the addition of oxygen forming carbondioxode, water and energy in the form of Adenine tri phosphate (ATP). In respiration process, carbondioxide is released in the atmosphere and oxygen is used for breakdown of food. This carbondioxide is used by the plants in the process of photosynthesis and oxygen is released in the atmosphere which is again used by animals for respiration.
Photosynthesis requires sunlight, carbon dioxide and water to produce glucose. This simple sugar is a carbohydrate that combines with other sugars to form the plant's structure and stores energy for future use. Hope it's useful!
