(a(i))[1]
Complete the sentence. Genes and alleles are composed of [BLANK].
(a(ii))[5]
Determine the phenotypes of the offspring when the unknown parent apple tree is heterozygous. Complete the genetic diagram: parental phenotypes disease-resistant \times not disease-resistant; parental genotypes [BLANK] \times [BLANK]; gametes [BLANK], [BLANK] \times [BLANK], [BLANK]; offspring genotype [BLANK]; offspring phenotype [BLANK].
(b(i))[2]
Explain the reason.
(b(ii))[1]
Suggest a way the farmer could make sure that only the chosen disease-resistant apple trees were pollinated.
(b(iii))[2]
Describe how artificial selection is different from natural selection.