Determine whether the study depicts an observational study or an experiment. A. Seventh dash grade students are randomly divided into two groups. B. One group is taught math using traditional techniques; the other is taught math using a reform method. C. After 1 year comma each group is given an achievement test to compare proficiency. D. nothing

As a result of a labeling mistake at the chemical factory, a farmer accidentally sprays weedkiller rather than fertilizer on half her land. as a result, she loses half of her productive farmland. if the property of diminishing returns applies to all factors of production, she should expect to seea. a decrease in the marginal productivity of her remaining land and an increase in the marginal productivity of her labor. b. an increase in the marginal productivity of her remaining land and an increase in the marginal productivity of her labor. c. an increase in the marginal productivity of her remaining land and a decrease in the marginal productivity of her labor. d. a decrease in the marginal productivity of her remaining land and a decrease in the marginal productivity of her labor.