Question

Photosynthesis is endothermic while respiration is exothermic , justify

Answer 1

During digestion,food is broken down into simplersubstances.For example carbohydrates during digestions are broken down into glucose.these glucose combines with oxygen in the cells and release energy.this type of reaction is called respiration.during this reaction energy is released hence it is an exothermic reaction.C6H12O6 +6O2 →6CO2 +6H2O + Energy

Answer 2

during photosynthesis, the sunlight is absorbed by leaf of plants to make food .so when the heat energy is absorbed ,it said to be endothermic.that"s why photosynthesis is considered as endothermic reaction. 

during respiration ,the glucose combine with oxygen in cells of body and releases energy which we utilise to get sufficient energy in the form of atp.
hence it releases energy which is of exothermic process.that"s why respiration considered exothermic