In a species of fish, the allele S S\,S for striped scales is dominant to the allele s s\,s for unstriped scales. A clutch produced by two striped fish contains both striped and unstriped offspring. A striped fish from this clutch is later mated with an unstriped fish.
Which pair gives both possible probabilities for the later mating to produce an unstriped offspring?
0%0\%0% or 50%50\%50%
50%50\%50% or 75%75\%75%
0%0\%0% or 75%75\%75%
25%25\%25% or 100%100\%100%
71 exam-style questions on Edexcel GCSE Biology 3.3 Inheritance, covering 3.3.1 Gregor Mendel and the basis of genetics, 3.3.2 Alleles and inherited characteristics, 3.3.3 Monohybrid inheritance, 3.3.4 Determination of sex at fertilisation, 3.3.5 Outcomes from monohybrid crosses, 3.3.6 Inheritance of ABO blood groups, 3.3.7 Inheritance of sex-linked disorders, and 3.3.8 Multiple genes and phenotypic features. Each one has a worked solution and a mark scheme showing where the marks go.