How did combat change in WWI as compared to previous wars?

Which of the following might cause the inflation rate to spike up sharply? the purchasing power of the average consumer decreases due to a sluggish economy. plentiful rainfall and moderate temperatures result in good harvests of wheat and soybeans. the items in the cpi market basket change to account for changing consumer buying habits. prices on world oil markets rise steeply due to war in the middle east.

The authors of the paper "fudging the numbers: distributing chocolate influences student evaluations of an undergraduate course"† carried out a study to see if events unrelated to an undergraduate course could affect student evaluations. students enrolled in statistics courses taught by the same instructor participated in the study. all students attended the same lectures and one of six discussion sections that met once a week. at the end of the course, the researchers chose three of the discussion sections to be the "chocolate group." students in these three sections were offered chocolate prior to having them fill out course evaluations. students in the other three sections were not offered chocolate. the researchers concluded that "overall, students offered chocolate gave more positive evaluations than students not offered chocolate." indicate whether the study is an observational study or an experiment. give a brief explanation for your choice.

Which feature of greece’s geography explains the ancient greeks’ need for trade? a. the mountainous landscape b. the dry summer climate c. the location along the seacoast d. the location along the boundary between asia and europe.