A Single,simple,recessively Inherited Mutation Inactivates the Enzyme That Converts Phenylalanine

Multiple Choice

A single,simple,recessively inherited mutation inactivates the enzyme that converts phenylalanine to tyrosine.Homozygous recessive individuals possess an excessive amount of phenylalanine and a deficiency of tyrosine.Additionally,these individuals may be mentally deficient,have abnormally light hair and abnormally light skin color.This disorder is an example of

A) incomplete penetrance.
B) incomplete dominance.
C) polygenic inheritance.
D) pleiotropy.