A fish breeder has selectively bred a line of trout for high body mass and resistance to a fungal disease. The breeder wants evidence that both characteristics are inherited rather than caused by differences in rearing conditions.
Which investigation would provide the strongest evidence?
Give selected-line offspring a high-energy ration and the other offspring a standard ration, expose both groups to the fungus and compare their body mass and disease damage.
Rear offspring from the selected line and offspring from the original mixed population on the same ration, expose both groups to the fungus and compare their body mass and disease damage.
Rear both groups on the same high-energy ration without the fungus, compare their body mass and use disease records from their parents to compare resistance.
Give both groups the same ration, expose only the selected-line offspring to the fungus and compare the body mass and disease damage recorded for each group.
80 exam-style questions on AQA GCSE Biology 6.2 Variation and evolution, covering 6.2.1 Variation, 6.2.2 Evolution, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, and 6.2.5 Cloning. Each one has a worked solution and a mark scheme showing where the marks go.