What this practice covers
These questions are drawn from past CIE 9700 Biology papers and filtered to inheritance. You answer, you find out immediately whether you were right, and you get the reasoning for the correct option and for each distractor. Wrong answers go to a mistakes locker so you can come back to exactly those.
Practice is free. You need an account only so your progress and your mistakes are still there next time.
Start practising practice questions →
What examiners see students get wrong here
These are the errors that cost marks on inheritance, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Saying homologous chromosomes carry the same alleles. They carry the same genes at the same loci, and often different alleles.
- Placing crossing over in meiosis II or in mitosis. It is prophase I.
- Saying anaphase I separates chromatids. It separates homologous chromosomes; anaphase II separates chromatids.
- Giving only crossing over as a source of variation, and leaving out random orientation and random fertilisation.
- Writing sex-linked genotypes as bare letters rather than showing the X and Y chromosomes.
- Saying a male carrier of haemophilia. A male has one X, so he is affected or he is not; only females can be carriers.
- Treating a departure from 9:3:3:1 as an experimental error rather than as evidence of linkage or epistasis.
- Using percentages or ratios in a chi-squared calculation instead of raw numbers.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Inheritance revision notes.