A nursery worker measures rose seedlings after one growing period. Healthy seedlings have a mean shoot length of 24 cm, but one group has a mean shoot length of 6 cm. The leaves of the shorter seedlings are still green and have no purple or black spots.
Which explanation best fits these observations?
Magnesium deficiency only
Rose black spot only
Both nitrate and magnesium deficiencies
Nitrate deficiency only
133 exam-style questions on AQA GCSE Biology 3.3 Plant disease, covering 3.3.1 Detection and identification of plant diseases and 3.3.2 Plant defence responses. Each one has a worked solution and a mark scheme showing where the marks go.