An indoor farm grows lettuce plants in water containing dissolved mineral salts. Salts can build up when the water is reused.
A technician investigated how salt concentration affected lettuce root tissue. The technician measured the percentage change in mass of the tissue.
| Salt concentration in g/dm³ | Percentage change in mass |
|---|---|
| 0 | +6.0 |
| 3 | +2.0 |
| 6 | −2.0 |
| 9 | −6.0 |
Explain the pattern in the results.
Suggest one additional salt concentration the technician should test to find more precisely the concentration that causes no net movement of water.
140 exam-style questions on AQA GCSE Biology 1.3 Transport in cells, covering 1.3.1 Diffusion, 1.3.2 Osmosis, and 1.3.3 Active transport. Each one has a worked solution and a mark scheme showing where the marks go.