The most common mineral group in earth's crust is the
a. oxides
b. carbonates
c. sulfides
d. silicates

Which of these was not a key difference between northern and southern states at the constitutional convention? wanting to protect states’ interests vs. a government with strict rules having more, larger cities vs. having fewer, smaller cities wanting to protect agriculture vs. protect industries having many enslaved people vs. using less enslaved labor

According to the federal regulations, which of the following studies meets the definition of research with human subjects? a study of twenty 4th grade classrooms in which researchers ask the schools to systematically vary the time of day reading is taught, and collect weekly assessments of reading comprehension for each child over a three-month period. the collection of data, by a playground designer hired by the superintendent of schools, about the physical dimensions of school playgrounds, presence of fencing, and the kinds of equipment currently provided. a feasibility study for implementing a year-round school program, focusing on economic issues such a facilities utilization and transportation costs. an analysis of aggregate data comparing statewide high school graduation rates provided by the state department of public instruction, using county tax information.

The primary purpose of a certificate of confidentiality is to: allow law enforcement to investigate abuse cases. protect researchers from disclosing conflicts of interest. prevent subjects from knowing the purpose of a study. protect identifiable research information from compelled disclosure.