Answer:
<h2>2. Peter's maternal grandfather has PKU.</h2>
Explanation:
- Such type of the genetic disorder in which two copies of a gene must be mutated at a time is called autosomal recessive disorder such as sickle cell anemia, phenylketonuria, and some other diseases.
- When a sing copy of a gene is mutated in a person then this disorder is not appeared and the person is called a carrier.
- So when a child is born by two carrier parents then there is a chance that a child will be affected if both the parents donate mutated genes.
- In the case of Peter, since peter does not show this defect this means his maternal grandfather was affected by this disorder.
It would help you know how they all work together like how the musicular system helps the digestive system during digestion
