Why does fossil fuel use in the United States make the U. S. vulnerable to the political wishes of foreign countries? a.
The US is a net exporter of fossil fuels.
b.
Fossil fuels lead to global climate change.
c.
The US imports much of its petroleum from foreign countries which set the prices.
d.
All of the above.

Flowchart with 6 boxes. box a sits at the very bottom of the left side of the flowchart, which flows into box b. box b flows into box c. box c flows into box d. on the bottom of the right side of the flowchart, box f flows into box e, and box e flows into box d. box d is the highest point in the flowchart. which of the following sections represent state-level courts? d, e, f b, e a, b, c a, f

Which choice best describes how your answer compares to the sample

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.