A nitrogen­-fixing microbe associated with Azolla in rice fields is

Correct answer: B. Anabaena

  • A. Spirulina
  • B. Anabaena
  • C. Frankia
  • D. Tolypothrix.

Explanation

Azolla plays a very important role in rice production. Azolla and its nitrogen­-fixing partner, Anabaena, have been used as green manure to fertilise rice paddies and increase production. With the help of Azolla, rice can be grown year after year, several crops a year, with little or no decline in productivity; hence no rotation of crops is necessary.

Last updated

About Man and His Environment

Ecosystems include biotic and abiotic components, food chains and webs, energy flow, nutrient cycles, populations and ecological relationships. Pollution and conservation cover air, water, soil and noise pollution, their effects on organisms, biodiversity loss, protected areas, sustainable resource use and methods for reducing environmental damage.

Practise Man and His Environment

382 free Man and His Environment MCQs from Biology, each with the correct answer and an explanation. Unlimited attempts, no account needed.

Exams that ask Biology questions like this

Biology is on 6 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.

Related questions