Scientists studied pairs of twins to find out how genes and the environment affect height and body mass.
Some identical twins were brought up together in the same home. Other identical twins were brought up apart in different homes.
The Table shows the results.
Table
| Type of twins | Mean difference in height in cm | Mean difference in body mass in kg |
|---|---|---|
| identical twins brought up together | 1.7 | 1.9 |
| identical twins brought up apart | 1.8 | 4.5 |
| non-identical twins brought up together | 4.4 | 4.6 |
Calculate how many times greater the mean difference in height is for non-identical twins than for identical twins brought up together.
Give your answer to one decimal place.
Explain why identical twins are useful for studying the causes of variation.
Explain what the results show about the effect of genes and the environment on height.
Explain what the results show about the effect of the environment on body mass.
40 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.