Single-Gene Disorders Are Described by All of the Following Except

Multiple Choice

Single-gene disorders are described by all of the following except  

A) they occur in 1 out of every 100 people.
B) they are cannot be tracked using a pedigree chart.
C) we know the most about them compared to other types of disorders.
D) they could be caused by dominant or recessive allele.
E) causative alleles may persist in the population due to a survival advantage.