Two genetic lines of laboratory mice, X and Y, were investigated. Mice within each line had the same inherited alleles. The inherited alleles of line X differed from those of line Y.
Mice from each line were given either a restricted or plentiful amount of food for 10 weeks. The table shows their mean body masses after 10 weeks.
| Genetic line | Amount of food | Mean body mass in g |
|---|---|---|
| X | restricted | 21.0 |
| X | plentiful | 27.0 |
| Y | restricted | 24.0 |
| Y | plentiful | 34.0 |
Explain what the results suggest about the causes of variation in body mass.
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.