The human blood-brain barrier is a type of filter that protects the brain from foreign invaders, including toxins and poisons. It is made, primarily, of what type of tissue?

Dr. Meyers is a behavioral geneticist. She is investigating whether school achievement has a genetic component. Which of the following scenarios would indicate to her that there is a large genetic component?

a. Dizygotic twins show greater similarities in school achievement than siblings born 2 years apart. b. Adopted children show great similarities in school achievement to their adopted parents than their biological parents. c. Monozygotic twins show greater similarities in school achievement than dizygotic twins. d. Siblings born 2 years apart show greater similarities in school achievement than dizygotic twins.

DSM-IV-TR classifies people along five axes and _____ disorders

a. interprets b. speculates on causes of c. describes symptoms of d. prescribes treatment for