UPSC Prelims 2018— Question 65

**Concept and analysis:** Carbon fertilization refers to the stimulation of photosynthesis and plant growth that can occur when atmospheric carbon-dioxide concentration rises, subject to species, nutrients, water, temperature and other constraints. It is distinct from the greenhouse warming effect and from ocean acidification. The term does not mean universal adaptation of all organisms to climate change. The question is testing precise UPSC-level identification rather than a broad association. The key is to distinguish the exact institutional, constitutional, historical, geographical, economic or scientific feature being asked. **Option-wise evaluation** **Option A:** Correct. Increased plant growth due to increased concentration of carbon dioxide in the atmosphere directly matches the concept or factual identification established in the analysis. **Option B:** Incorrect. Increased temperature of Earth due to increased concentration of carbon dioxide in the atmosphere is a different institution, place, definition, proposition or description and does not satisfy the specific requirement of the question. **Option C:** Incorrect. Increased acidity of oceans as a result of increased concentration of carbon dioxide in the atmosphere is a different institution, place, definition, proposition or description and does not satisfy the specific requirement of the question. **Option D:** Incorrect. Adaptation of all living beings on Earth to the climate change brought about hr the increased concentration of carbon dioxide in the atmosphere is a different institution, place, definition, proposition or description and does not satisfy the specific requirement of the question. **UPSC takeaway:** The safest way to solve this type of question is to anchor the answer in the defining feature of the concept and then test every option against that feature. Closely related institutions or terms are often used as distractors. In statement-based questions, do not judge the option as a whole before checking each statement independently. In factual questions, compare the wording of each option with the exact definition, location, institutional role, chronology or scientific property. The correct answer follows from that verification rather than from familiarity with a keyword.