The sex chromosomes determine the sex of a baby.
What are the sex chromosomes of a human male and of a human female?
The data in the table shows the ratio of males to females in a certain country:
| Ratio of males to females | |
|---|---|
| At birth | 105 males : 100 females |
| Average over the whole population | 92 males : 100 females |
What percentage of babies are male at birth? Give your answer to 1 decimal place.
In a maternity clinic, 820 babies are born in a year. Calculate how many of them are likely to be male.
On average, men do not live as long as women. How does the data in the table show this?
97 exam-style questions on OCR GCSE Biology 5.1 Inheritance, covering 5.1.1 The genome, 5.1.2 Environment and phenotype, 5.1.3 Variants and mutations, 5.1.4 How genetic variants influence phenotype, 5.1.5 Asexual and sexual reproduction, 5.1.6 Haploid and diploid, 5.1.7 Meiotic cell division, 5.1.8 Single gene inheritance, 5.1.9 Predicting single gene crosses, 5.1.10 Sex determination, 5.1.11 Multiple gene inheritance, and 5.1.12 Development of our understanding of genetics. Each one has a worked solution and a mark scheme showing where the marks go.