Problem:
Question: Which of the following statements about phenylketonuria (PKU) is false?
1. Buildup of phenylpyruvic acid affects the nervous system.
2. The amino acid tyrosine cannot be made.
3. Production of the hormone thyroxin s affected.
4. The skin color of those with phenylketonuria is light because of decreased levels of melanin.
5. Adrenalin levels increase in the blood stream.
Please provide correct answer.