Hugo, almost two years old, was learning to talk. His family spoke both Spanish and English, switching back and forth between the two, so Hugo found himself using two languages. The type of plasticity that applies to Hugo and his languages is

All smoking diseases are

A. dose and duration sensitive. B. decreasing worldwide. C. destructive only to the lungs and respiratory system. D. less likely to affect African Americans.

Dr. Sardonicus wants to know whether or not the first three years of life are critical for acquiring language. She decides to study a child who was tragically deprived of human language by her parents. This type of research is called a(n) ________

a. correlational study. b. experiment. c. survey. d. case study.