Unlike ________ twins,who develop from a single fertilized egg,________ twins develop from separate fertilized eggs.

A) fraternal; identical
B) identical; fraternal
C) placental; nonplacental
D) nonplacental; placental

Before asking people to participate in a research project, an investigator must provide them with a document providing __________.

A) a meta-analysis
B) debriefing
C) open practices
D) informed consent

Ralph just started taking guitar lessons last week.Jimmie has been playing guitar for almost 20 years.According to the concept of social facilitation, performing in front of an audience of strangers and friends tonight is likely to _____ Ralph's performance and _____ Jimmie's performance.

A) decrease/decrease
B) increase/enhance
C) decrease/enhance
D) increase/decrease

Mr.Sanderson is a 1^st grade teacher.He believes in fostering children's tolerance for others,encouraging fairness,and promoting cooperative behavior.One of his classroom jobs involves leading the lunch line to the school cafeteria,a coveted role among the students.Vanessa has been line leader of the week.It is now the last day of the week and Mr.Sanderson asks Vanessa to allow Jeremy,a brand new student,a chance to lead the line.Mr.Sanderson is upset with Vanessa when she refuses because he feels she is not being kind.What is the best explanation for Vanessa's behavior at this age?

A) Vanessa is at the premoral stage and is unconcerned about other children.
B) Vanessa can engage in needs-based reasoning but may still have difficulty weighing the needs of others against her own.
C) Vanessa recognizes her duty to share,but she doesn't like the new student.
D) Vanessa can't engage in needs-based reasoning so she is unaware that she is being selfish.

According to a study (Farley, 2003) , what percentage of streetwalkers had been raped?

A) 15 percent
B) 75 percent
C) 25 percent
D) 60 percent

Anthropologists would posit that social psychologists cannot understand human behavior fully unless they understand the ____.

A) genetic makeup of the populations under study
B) relationship between humans and animals
C) biological basis of the behavior
D) cultural context in which that behavior occurs