Consider the following organisms : 1. Agaricus 2. Nostoc 3. Spirogyra Which of the above is/are used as biofertilizer/biofertilizers?
- A(a) 1 and 2
- B(b) 2 onlyCorrect
- C(c) 2 and 3
- D(d) 3 only
Explanation
The correct answer is B) 2 only (Nostoc).
Nostoc is a cyanobacterium (blue-green algae) capable of nitrogen fixation. This means it converts atmospheric nitrogen into ammonia, a form usable by plants. Therefore, it's widely used as a biofertilizer, particularly in rice paddies.
Agaricus is a genus of mushrooms. While beneficial as a food source and in decomposition, it doesn't fix nitrogen and isn't used as a biofertilizer.
Spirogyra is a filamentous green algae. It contributes to oxygen production through photosynthesis but doesn't fix nitrogen and isn't a biofertilizer.
Therefore:
Option A (1 and 2) is incorrect because Agaricus is not a biofertilizer.
Option C (2 and 3) is incorrect because Spirogyra is not a biofertilizer.
Option D (3 only) is incorrect because Spirogyra is not a biofertilizer.
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