The process of respiration is the opposite to photosynthesis. Insects, plants and all creatures respire. They use the energy trapped in the food they have eaten or in the case of plants food they have made. When living organisms respire they release the energy trapped in the food and use this energy to move muscles and sustain all the essential activities for life. During respiration oxygen is combined with food to release energy and produce carbon dioxide and water.
A diagram of a plant cell showing the process of respiration. Note how oxygen and sugar are taken in by the cell and how carbon dioxide and water along with the vital energy are released. We are so lucky that plants produce more oxygen during photosynthesis than they use during respiration. Otherwise we would have no oxygen for animals to use.
On a cold Winter's night an unwise person, who delighted in collecting indoor plants, decided to move all his plants into his bedroom where it was warm. He closed the door and sealed off the room so no heat can escape. He was found dead the next morning. Explain the cause of death.