What invention effectively ended the era of the "long drives" of the late 19th century?
a. barbed wire
b. the cotton gin
c. the steel plow
d. the refrigerated box car

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.

What is a common factor all nonprofit businesses share? they pay no income tax.they have no capital.they are national in scope.they perform charitable acts.

Why is this statement not a hypothesis? sunflowers require soil and plenty of sunlight and water to grow and thrive. a. it is a well-known fact. b. it is a proven theory. c. it is not falsifiable. d. it is difficult to test.