Professional and amateur athletes are often tested for the use of illegal performance-enhancing drugs. Which of the following processes is used to separate these chemicals from a blood or urine sample? a. fractionation b. chromatography c. osmosis d. distillation

The nature–nurture issue refers to the debate over the relative contributions that make to the development of psychological traits. a. introspection and nerve cell activity b. unconscious and conscious motives c. behavior and mental processes d. genes and experience