The table describes stages in the nitrogen cycle.
Complete the table by naming or describing each stage.
The first one has been done for you.
| Description of stage | Name of stage |
|---|---|
| Plants absorb nitrate ions from the soil to synthesise amino acids and proteins. | assimilation |
| Soil bacteria convert ammonium ions into nitrite ions, and then into nitrate ions. | |
| Anaerobic bacteria convert soil nitrates into nitrogen gas, reducing soil fertility. | |
| nitrogen fixation |
An accidental discharge of organic slurry from a livestock holding tank enters a nearby slow-moving stream.
Describe the biological consequences of this discharge on the stream ecosystem.
12 exam-style questions on Edexcel IGCSE Biology Cycles within ecosystems. Each one has a worked solution and a mark scheme showing where the marks go.