If a cell is experiencing myelination, it is

Which statement about correlational research is true?

a. It is a powerful way to establish causal relationships between variables. b. It allows a researcher to establish cause-and-effect relationships. c. It permits researchers to determine whether one variable is predictive of another. d. It is limited to the study of variables that can be measured in the laboratory.

Which of the following is a characteristic of Rett's disorder?

A) The loss of previously acquired skills, such as the ability to walk and to communicate after three years of apparently normal development B) Stereotyped behavior from birth C) A loss of hearing at birth D) A range of physical, behavioral, motor, and cognitive abnormalities that begin after a few months of normal development