UPSC Prelims 2018— Question 86

**Concept and analysis:** Prosopis juliflora is an invasive plant introduced into many dry and semi-arid regions. Where it spreads aggressively, it can displace native vegetation, alter habitats and reduce local biodiversity. Its environmental significance in India is therefore primarily connected with invasiveness and ecological impacts rather than the specific cosmetic or pesticide-extract uses listed. 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:** Incorrect. Its extract is widely used in cosmetics. is a different institution, place, definition, proposition or description and does not satisfy the specific requirement of the question. **Option B:** Correct. It tends to reduce the biodiversity in the area in which it grows. directly matches the concept or factual identification established in the analysis. **Option C:** Incorrect. Its extract is used in the synthesis of pesticides. is a different institution, place, definition, proposition or description and does not satisfy the specific requirement of the question. **Option D:** Incorrect. None of the above 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.