UPSC Prelims 2014— Question 65

Correct answer: Option B. Photosynthesis converts radiant energy from sunlight into chemical potential energy stored in organic molecules. In simplified terms, light energy drives the formation of energy-rich compounds that ultimately support carbohydrate synthesis. The process is therefore an example of converting free/radiant energy into stored chemical potential energy, not oxidation of food. Option A: Incorrect. This option does not match the verified answer because its proposition, location, institution, sequence, or combination conflicts with the relevant fact tested in the question. The option reads: “Potential energy is released to form free energy” Option B: Correct. This option is consistent with the governing fact or the valid combination identified in the question. The option reads: “Free energy is converted into potential energy and stored” Option C: Incorrect. This option does not match the verified answer because its proposition, location, institution, sequence, or combination conflicts with the relevant fact tested in the question. The option reads: “Food is oxidized to release carbon dioxide and water” Option D: Incorrect. This option does not match the verified answer because its proposition, location, institution, sequence, or combination conflicts with the relevant fact tested in the question. The option reads: “Oxygen is taken, and carbon dioxide and water vapour are given out” The key Prelims lesson is to test each proposition independently before selecting the combination. Where the question uses words such as 'only', 'all', 'none', 'always' or a precise institutional/geographical association, a single inaccurate component is sufficient to eliminate the option. The answer recorded here follows the official answer key for the question-paper series represented by the uploaded source and has been cross-checked against an independent published key. The explanation is intended for conceptual revision rather than as a reproduction of any third-party solution.