PKU, Tay-Sachs Disease, and Galactosemia Have in Common the Fact

Multiple Choice

PKU, Tay-Sachs disease, and galactosemia have in common the fact that they are all

A) accompanied by sudden decreases in IQ during adolescence.
B) forms of mental retardation produced by poor maternal diet during pregnancy.
C) genetically-based disorders accompanied by low intelligence.
D) the results of hormonal deficiencies prenatally or during infancy.