Nitrogen fixation can be carried out by

  1. decomposers releasing CO₂
  2. denitrifying bacteria
  3. lightning and nitrogen-fixing bacteria
  4. plants' leaves
Answer

C) lightning and nitrogen-fixing bacteria

Lightning and bacteria fix nitrogen. O Level Biology · Topic 19 Relationships of Organisms with One Another and with the Environment · 19.2 Nutrient cycles

Biology MCQ · More O Level Biology: Organisms and the Environment MCQs · Practise