What molecules do plants produce using nitrogen?
Fats
Proteins
Sugars
In which form is nitrogen taken up by non-legume plants?
Nitrogen gas from the air
Nitrates from the soil
Protein from the soil
In which form do animals gain nitrogen?
Ammonium
Nitrate
Protein
The diagram below shows part of the nitrogen cycle.
Which of the numbered stages involve bacteria?
1 and 3
2 and 4
3 and 4
Which stage is decomposition?
2
3
4
Which reaction shown below is carried out by denitrifying bacteria?
\[\text{ammonium} \to \text{nitrate}\]
\[\text{nitrate} \to \text{nitrogen\,gas}\]
\[\text{nitrogen\,gas} \to \text{ammonium}\]
Which group of bacteria use nitrogen gas from the air to produce their own nitrate?
Denitrifying bacteria
Nitrifying bacteria
Nitrogen-fixing bacteria
Which stage is nitrification?
Stage A
Stage B
Stage C
Which kind of organisms are decomposers?
Bacteria and fungi
Fungi and insects
Insects and bacteria
Why do decomposers break down plant and animal waste products?
To keep the nitrogen cycle going
To produce ammonium
To obtain energy