(a(i))[1]
Using the symbols in the key, fill in Fig. 3.1 with the chromosome sets of T. aestivum.
(a(ii))[4]
At the positions marked Y and Z in the hybridisation sequence, a fertile hybrid arose from a sterile one. Explain why the hybrid (AB) is sterile and what happened at the point marked Y in Fig. 3.1.
(b(i))[4]
Discuss how far these experiments support the idea that E$\beta$F acts as an alarm signal for aphids.
(b(ii))[3]
Other experiments show that E$\beta$F attracts predators of aphids, such as ladybirds. Explain how growing genetically modified wheat secreting E$\beta$F could increase the yield of wheat.
(b(iii))[3]
Suggest why some people who oppose growing genetically modified insect-resistant maize or cotton might accept this genetically modified wheat.