Monozygotic twins are more commonly called __________ twins even though they are not

A critical feature of multiple-baseline designs is that:

a. baselines differ in length b. treatment is staggered over time c. A and B d. none of these

People who tend to remain as volunteers over an extended time period ______.

A. tend to be from high SES backgrounds B. tend to be motivated by a desire for knowledge or greater understanding C. tend to have extremely high altruistic motives D. are more likely to be from rural areas