Two students performed an experiment to illustrate inheritance. They each made a 'spinner' similar to the one shown in [Figure 2.1]. A result is recorded when a disc is spun and stops with one side nearest the surface.

1. (a)Complete Table 2.1, to show the expected results if the two students spin their discs, at the same time, on 80 separate occasions. Table 2.1: | combination of letters on each occasion | number of times each combination of letters is recorded |. | A and A | 20 |. | A and a | |. | a and a | |.[1]
2. (b)Suggest two reasons why the results they obtained may have been different from the expected results.[2]
3. (c)(i)Suggest the feature or stage in the process of inheritance represented by each of the following: (i) the students[1]
4. (c)(ii)Suggest the feature or stage in the process of inheritance represented by each of the following: (ii) the spinning of the disc[1]
5. (c)(iii)Suggest the feature or stage in the process of inheritance represented by each of the following: (iii) the letters on the disc[1]
6. (d)Describe how the students could modify their spinners and use them to illustrate the possible inheritance of blood groups by children of a father who has codominant blood group alleles and a mother who is heterozygous for blood group A.[5]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.