UPSC CSE Prelims

Correct Option: A (1, 3 and 4 only) Explanation: Alfalfa, chickpea and clover are legumes with symbiotic nitrogen-fixing rhizobia; amaranth, purslane and spinach are not conventional nodulated nitrogen fixers. Statement / Pair / Item-wise Analysis: 1. True / qualifies - Alfalfa (lucerne) fixes atmospheric nitrogen through root-nodule bacteria. 2. False / does not qualify - Amaranth is not a nitrogen-fixing legume. 3. True / qualifies - Chickpea forms nitrogen-fixing legume nodules. 4. True / qualifies - Clover forms rhizobial root nodules. 5. False / does not qualify - Purslane does not conventionally fix atmospheric nitrogen through symbiotic nodules. 6. False / does not qualify - Spinach is not a nitrogen-fixing crop. Option-wise Analysis: A. Correct-selects exactly the correct statements/items identified above. B. Incorrect-includes 5 even though Purslane does not conventionally fix atmospheric nitrogen through symbiotic nodules.; includes 6 even though Spinach is not a nitrogen-fixing crop.; omits 4 even though Clover forms rhizobial root nodules. C. Incorrect-includes 2 even though Amaranth is not a nitrogen-fixing legume.; includes 5 even though Purslane does not conventionally fix atmospheric nitrogen through symbiotic nodules.; includes 6 even though Spinach is not a nitrogen-fixing crop.; omits 1 even though Alfalfa (lucerne) fixes atmospheric nitrogen through root-nodule bacteria.; omits 3 even though Chickpea forms nitrogen-fixing legume nodules. D. Incorrect-includes 2 even though Amaranth is not a nitrogen-fixing legume.; includes 5 even though Purslane does not conventionally fix atmospheric nitrogen through symbiotic nodules.; includes 6 even though Spinach is not a nitrogen-fixing crop.; omits 3 even though Chickpea forms nitrogen-fixing legume nodules.