| Date | November 2015 | Marks available | 2 | Reference code | 15N.3.SL.TZ0.17 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Outline | Question number | 17 | Adapted from | N/A |
Question
Outline the process of nitrogen fixation by a named free-living bacterium.
Markscheme
a. atmospheric nitrogen is converted to ammonia;
b. by Azotobacter;
Do not accept Rhizobium.
Examiners report
Many weaker candidates referred to Rhizobium.
Syllabus sections
Option C: Ecology and conservation » Option C: Ecology and conservation (Additional higher level topics) » C.6 Nitrogen and phosphorus cycles
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