A fruit farm grows strawberry plants in a hydroponic system. The table shows how nitrate concentration affects the mean mass of strawberries harvested from each plant.
| Concentration of nitrate in mg/dm3\text{mg/dm}^3mg/dm3 | 40 | 80 | 120 | 160 |
|---|---|---|---|---|
| Mean mass of strawberries per plant in g | 320 | 438 | 476 | 489 |
Higher nitrate concentrations make each tank of nutrient solution more expensive to prepare. The farm must achieve a mean mass of at least 460 g of strawberries per plant.
Which nitrate concentration is the least expensive choice that meets the farm's requirement?
40 mg/dm340\text{ mg/dm}^340 mg/dm3
160 mg/dm3160\text{ mg/dm}^3160 mg/dm3
120 mg/dm3120\text{ mg/dm}^3120 mg/dm3
80 mg/dm380\text{ mg/dm}^380 mg/dm3
127 exam-style questions on OCR GCSE Biology 6.2 Feeding the human race, covering 6.2.1 Biological factors affecting food security, 6.2.2 Agricultural solutions to growing demand, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, 6.2.5 Steps in genetic engineering, 6.2.6 Benefits and risks of gene technology in agriculture, and 6.2.7 Biotechnological solutions to growing demand. Each one has a worked solution and a mark scheme showing where the marks go.