Cyanobacteria as Biofertilisers — NEET Biology
📚 Practice ConceptCyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen, e.g. Anabaena, Nostoc, Oscillatoria, etc. In paddy fields, cyanobacteria serve as an important biofertiliser. Blue green algae also add organic matter to the soil and increase its fertility. Currently, in our country, a number of biofertilisers are available commercially in the market and farmers use these regularly in their fields to replenish soil nutrients and to reduce dependence on chemical fertilisers.
Which statements about biofertilisers are correct? 1. Rhizobium fixes nitrogen in root nodules. 2. Azospirillum and Azotobacter fix nitrogen free-living in soil. 3. Glomus forms mycorrhiza and improves tolerance to salinity. 4. Cyanobacteria like Anabaena enrich paddy fields. 5. Biofertilisers reduce nutrient quality of soil.
View solution & NCERT explanation
Correct answer: B — 1, 2, 3, 4 only
All four are correct; biofertilisers increase soil fertility, not reduce it.
What does NCERT say about Cyanobacteria are autotrophic microbes?
Has this concept appeared in NEET?
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.