The male birds of many species are most likely to learn
A) any birdsong that they hear during the motor phase.
B) the songs of their own species that they hear during the motor phase.
C) any birdsong that they hear during the sensory phase.
D) the songs of their own species that they hear during the sensory phase.
E) any birdsong that they hear once they have reached maturity.
Question 2
The sensitive period for PKU is the early period during which
A) identified sufferers are fed phenylalanine-reduced diets.
B) excessive phenylalanine has substantial effects on neural development.
C) the symptoms of PKU are most severe.
D) both A and B
E) none of the above