The correct option is B A-Photosynthesis; B-Respiration
Green plants synthesise their own food in the form of an organic molecule i.e., glucose by utilising carbon dioxide and water in the presence of sunlight and chlorophyll by the process of photosynthesis(A). Oxygen is released as the by-product of this process.
This organic molecule i.e., glucose is utilised by the plants and animals to generate energy by the process of respiration (B). As a result of respiration, carbon dioxide and water is released as by-products.