Juvenile freshwater fish from the same two biological parents were divided at random between two tanks. All conditions apart from water temperature were kept the same.
After 12 weeks, the mass of each fish was measured.
| Water temperature in °C | Range of masses in g | Mean mass in g |
|---|---|---|
| 18 | 3.2–5.6 | 4.4 |
| 24 | 4.0–6.8 | 5.5 |
A student concludes that water temperature is the only cause of the variation in mass.
Evaluate the student's conclusion.
96 exam-style questions on Edexcel GCSE Biology 3.4 Variation and the Human Genome Project, covering 3.4.1 Causes of variation, 3.4.2 Outcomes of the Human Genome Project, 3.4.3 Genetic variation within a population, and 3.4.4 Effects of genetic mutations on phenotype. Each one has a worked solution and a mark scheme showing where the marks go.