According to jean piaget, in what stage of cognitive development are children able to understand conservation tasks?

a formal operational

b preoperational

c sensorimotor

d concrete operational

What new form of music swept the nation in the 1950s a. chamber music b. hip-hop c. jazz d. rock-and-roll

Identify the example of when situation and time are key to assessing risk of harm in a research study: a study on the efficacy of a behavioral intervention for smoking cessation involves both adults and teenagersasking women if they have had an abortionresearch on the prevalence of hiv-infected individuals in communitiesa survey about sexually transmitted diseases

In ancient egypt, the pharaoh collected from the peasant farmers. a. oil b. gold c. lumber d. taxes