Answer:
(i) An allele is a variant of a gene, can either be short or tall.
Dominant = the tall allele that "trumps" the short allele. if a dominant and recessive allele is present (heterozygous) then the dominant phenotype will be shown.
(ii) David's eyes are Brown
(iii) Sarah's eyes are blue
(iv) David - B, b
Sarah - b, b
(v) Possible genotypes include Bb and bb. These give the phenotypes of brown eyes or blue eyes.
(vi) The chance for blue eyes is 50% (or 1:1 ratio)
