A grower uses hydroponics to grow lettuces. The grower tests different concentrations of nitrate in the solution. Table
| Concentration of nitrate in mg/dm3\text{mg/dm}^3mg/dm3 | 0 | 50 | 100 | 150 | 200 |
|---|---|---|---|---|---|
| Mean mass of one lettuce in g | 120 | 210 | 280 | 300 | 300 |
| Nitrate costs money to buy. | |||||
| Which concentration should the grower use to produce the largest lettuces at the lowest cost? |
100 mg/dm3100\text{ mg/dm}^3100 mg/dm3
200 mg/dm3200\text{ mg/dm}^3200 mg/dm3
50 mg/dm350\text{ mg/dm}^350 mg/dm3
150 mg/dm3150\text{ mg/dm}^3150 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.