Given the map of the average cotton yield around the world, which of the following statements can be inferred about the regions in which cotton is produced?

a. cotton grows well in regions that are densely populated
b. the region in which cotton originated remains the worlds primary producer of cotton
c. a countries level of development is more likely than climate to predict the location of cotton producers
d. cotton is a plant that is best grown in the semiarid regions of the world
e. africa is still the largest producer of cotton in the world

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.