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Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYMicrobes in Human Welfare1 Mark
Question
Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
  3. Assertion is true but reason is false.
  4. Both assertion and reason are false.
Assertion: Azotobacter fixes nitrogen in symbiotic form.
Reason: Azotobacter form root nodules in the roots of leguminous plants.
✓

Answer

  1. Both assertion and reason are false.

Solution:

Azotobacter is a non-symbiotic nitrogen fixing bacteria that is it lives freely in the soil and perform nitrogen fixation. It is saprotrophic living on organic remains. Root nodules are formed by Rhizobium, a symbiotic nitrogen fixing bacteria.

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