Biology 9700 · AS & A Level · Cells as the basic units of living organisms

Cells as the basic units of living organisms — practice question

The diagram illustrates part of the nitrogen cycle. Which number sequence correctly indicates the roles played by different kinds of microorganism in the nitrogen cycle?

  • Adecomposing (putrefying) bacteria: 2; denitrifying bacteria: 4; nitrifying bacteria: 3
  • Bdecomposing (putrefying) bacteria: 3; denitrifying bacteria: 1; nitrifying bacteria: 2
  • Cdecomposing (putrefying) bacteria: 3; denitrifying bacteria: 1; nitrifying bacteria: 4
  • Ddecomposing (putrefying) bacteria: 4; denitrifying bacteria: 2; nitrifying bacteria: 1

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