UPSC Prelims 2014— Question 99

Correct answer: Option C. Volcanic activity, respiration and decomposition of organic matter release carbon dioxide into the atmosphere and therefore add carbon to the active carbon cycle. Photosynthesis does the reverse by removing atmospheric carbon dioxide and incorporating carbon into organic matter. Hence statements 1, 2 and 4 are correct. 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: “1 and 3 only” Option B: 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: “2 only” Option C: Correct. This option is consistent with the governing fact or the valid combination identified in the question. The option reads: “1, 2 and 4 only” 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: “1, 2, 3 and 4” 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.