Final answer:
Given that the mother is a carrier of an X-linked recessive disease and the father is normal, 50% of the sons will be affected by the disease and 0% of the daughters will be affected, although daughters have a 50% chance of being carriers. Therefore correct option is D
Step-by-step explanation:
When discussing X-linked recessive disorders, it's important to understand the inheritance patterns. X-linked recessive conditions are more frequently expressed in males because they only have one X chromosome. If a male inherits the affected X chromosome, he will display the disorder as he lacks a second X chromosome, which could carry a normal version of the gene to mask the condition.
In a scenario where the mother is a carrier (Xx) and the father is normal (XY), none of the daughters will exhibit the disease since they will inherit a normal X chromosome from their father. However, they have a 50 percent chance of being carriers. Sons, on the other hand, will have a 50 percent chance of being affected, as they would inherit the affected X chromosome from their mother and they only receive a Y chromosome from their father, which does not have the normal version of the gene.
Therefore, when answering the question of what percentage of the offspring will have this recessive X-linked disease, the answer is 50% for the sons and 0% for the daughters in terms of exhibiting the disease.
To illustrate this pattern, let's use an example: If a carrier mother (who has one copy of the disease gene on one of her X chromosomes) and a normal father have children, each son has a 50% chance of having the disease, and each daughter has a 50% chance of being a carrier, but will not show the disease because she also inherits a normal X chromosome from the father.