(a)[4]
Outline how selective breeding has been applied to improve maize.
(b)[3]
Fig. 4.1 shows part of a maize cob. A cob is made up of many individual seeds called kernels. Each kernel is produced by a separate fertilisation between a male and a female gamete. Some kernels are yellow and some are purple. Name the type of variation shown in Fig. 4.1. Suggest a genetic explanation for this colour pattern.
(c(i))[4]
Describe and suggest an explanation for the link between the area of Bt crops grown and the number of resistant pest species.
(c(ii))[2]
Suggest one social advantage and one environmental advantage of growing this Bt maize.