(a) During respiration, glucose is oxidised to give carbon dioxide and water along with energy.
Equation for respiration:
Photosynthesis is the process in which green plants synthesise their food (glucose) with the help of sunlight. In this process, carbon dioxide combines with water to form glucose.
Equation for photosynthesis:
Hence, what is given out in respiration is used in photosynthesis.
(b)