A multi-level indoor farm produces basil for sale as dried herb. The farm tested different treatments on equal areas of stacked growing trays. All other conditions were kept the same.
| Treatment | Temperature (°C) | Carbon dioxide concentration (%) | Lighting | Mean dry mass harvested each week (kg) | Extra weekly cost (£) |
|---|---|---|---|---|---|
| No added control | 14 | 0.04 | Daylight | 150 | 0 |
| Supplementary lighting | 14 | 0.04 | Daylight and lamps | 161 | 180 |
| Heating | 25 | 0.04 | Daylight | 215 | 140 |
| Carbon dioxide enrichment | 14 | 0.12 | Daylight | 158 | 90 |
| Heating and carbon dioxide enrichment | 25 | 0.12 | Daylight | 290 | 260 |
| Heating, carbon dioxide enrichment and supplementary lighting | 25 | 0.12 | Daylight and lamps | 304 | 500 |
The dried basil is sold for £5.00 per kg. Other production costs are the same for every treatment.
Explain the pattern in the results and why the farm should use the treatment that gives the greatest weekly return. Include calculations in your answer.
68 exam-style questions on AQA GCSE Biology 4.1 Photosynthesis, covering 4.1.1 Photosynthetic reaction, 4.1.2 Rate of photosynthesis, and 4.1.3 Uses of glucose from photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.