Explanation

Photosynthesis is endothermic because green plants absorb light energy to drive the conversion of carbon dioxide and water into glucose and oxygen, storing energy in chemical bonds. Combustion of carbon releases heat (exothermic), the neutralisation of an acid with an alkali releases heat (exothermic), and respiration breaks down glucose to release energy (exothermic). Only photosynthesis takes in energy from the surroundings, making it the endothermic process.