Question 1
A pea plant of genotype BB is crossed with one of genotype bb, and the F1 are allowed to cross among themselves. What percentage of the F2 has the same genotype as one of the original parents?
The right answer is the one marked above.
50 per cent. The F1 are all Bb. Crossing them gives 1 BB : 2 Bb : 1 bb, so the BB and bb boxes together are two of the four.
Asked about the F1 instead, the answer would be 0 per cent — every F1 plant is Bb, which matches neither parent. That is the fault in the printed question.