(a)[2]
State the number of people in Fig. 5.1 who have: XY chromosomes only one $I^A$ allele.
(b)[2]
Explain how Fig. 5.1 shows that blood group is an example of discontinuous variation.
(c)[1]
State one example of discontinuous variation found in plants.
(d)[2]
Explain why blood group inheritance is an example of codominance.
(e)[4]
Complete the genetic diagram to work out the probability that the offspring will have blood group AB.