Concept:An endothermic reaction strictly requires a continuous input of energy (heat, light, or electrical) from the surroundings to proceed.
Formula:$$ 6CO_2 + 6H_2O + \text{Light Energy} \rightarrow C_6H_{12}O_6 + 6O_2 $$
Solution:- Photosynthesis is the process by which green plants convert carbon dioxide and water into glucose.
- Because this reaction is utterly dependent on absorbing incoming solar photon energy to drive the non-spontaneous uphill synthesis of sugar, it is heavily endothermic.
Why other options are incorrect:Nuclear fission releases world-ending amounts of energy (highly exothermic). Synthesis of ammonia (Haber process) is exothermic (\( -92 \text{ kJ} \)). Oxidation reactions (combustion-like) are universally exothermic.
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