Jean Piaget based his ideas about infants' cognitive development on his detailed observations of his own three children. This is an example of what research method?

The 1906 U.S. law that prohibited interstate commerce in adulterated or misbranded foods and drugs was called the

A. Controlled Substances Act. B. Pure Food and Drugs Act. C. Prescription Drug Act. D. Patent Medicines Act.

Miranda says "more apple." This two-word utterance is an example of

A) an underextension. B) babbling. C) telegraphic speech. D) a referential style.