Final answer:
When a carrier of the albino allele (like Mark) has children with an individual with albinism (like Maude), there is a 50% chance that their children will be albinos, as albinism is a recessive genetic condition.
Step-by-step explanation:
The question deals with the inheritance of recessive alleles, specifically the allele for albinism, which is a genetic condition characterized by the absence of pigment in the skin, hair, and eyes. As albinism is a recessive trait, both parents must carry the gene for a child to express the condition. In the given scenario, Mark carries the allele for albinism and is thus a carrier (which means he has one copy of the albino allele and one normal allele), and Maude who is albino has two copies of the albino allele.
When they have children, there is a 50% chance their children will be albinos. This is because there is a 50% possibility for each child to inherit the recessive albino allele from Mark and another from Maude, resulting in the phenotype of albinism (aa).