Nitrogen cycle

Which process involves decomposers?

• W

• X

• Y

• Z

Which of the following processes will occur faster when the soil becomes poorly aerated?

• Y only

• Z only

• W and Z only

• X and Y only

Which of the following combinations correctly identifies the labelled processes shown in the diagram?

• I: decomposition

  II: photosynthesis

  III: respiration

• I: photosynthesis

  II: respiration

  III: decomposition

• I: respiration

  II: photosynthesis

  III: decomposition

• I: respiration

  II: decomposition

  III: photosynthesis

[DSE 2014; 45%]

Which of the following processes releases nitrogen-containing compounds from organisms back into the environment?

• Nitrification

• Decomposition

• Denitrification

• Nitrogen fixation

[CE 2010; 31%]

If all the decomposers in a habitat died out,

• the total biomass of the habitat would decrease.

• less energy would be available to the plants in the habitat.

• the number of animals in the habitat would remain unchanged.

• no nitrogenous compounds would be available for the plants in the habitat.

[CE 2006; 30%]

In the nitrogen cycle, which process(es) involve(s) decomposers?

(1)  conversion of protein to ammonium ion

(2)  conversion of ammonium ion to nitrite

(3)conversion of nitrate to nitrogen gas

• (1) only

• (1) and (2) only

• (2) and (3) only

• (1), (2) and (3)