Haemophilia is a sex-linked disorder in which a single protein of the blood-clotting cascade is affected, so even a small cut can bleed without stopping. Evaluate the Assertion about how often the disorder appears in each sex and the Reason offered for it.

• Assertion (A): Haemophilia is much more commonly observed in human males than in human females.
• Reason (R): Haemophilia is caused by a recessive allele located on the X chromosome, so a male needs only one copy of the allele to be affected, whereas a female needs two copies.