Listen to part of a lecture in an Earth Science class. The class has been discussing volcanoes.
- What is the lecture mainly about?
- A. Ways to determine the ages of volcanic islands
- B. Criteria for classifying various types of volcanoes
- C. Explanations for why volcanoes occur in some locations
- D. Methods for measuring magma produced by volcanoes
- According to the professor, why was the hot spot theory originally proposed?
- A. To explain prolonged volcanic activity far from plate boundaries
- B. To explain why volcanoes form both on land and in the ocean
- C. To explain variations in the amounts of magma produced by volcanoes
- D. To explain why volcanoes may become inactive after millions of years
- Why does the professor describe moving a sheet of heavy paper over a candle?
- A. To clarify that plumes do not produce great amounts of heat
- B. To describe an experiment he would like the students to conduct
- C. To illustrate one hypothesis for the way some volcanic anomalies are formed
- D. To emphasize the thinness of some of Earth’s tectonic plates
- Why does the professor discuss how high one of the Hawaiian Islands rises above the ocean floor?
- A. To provide evidence supporting the plume hypothesis
- B. To compare the Hawaiian Island to other volcanic islands in the Pacific Ocean
- C. To point out a common difference between volcanic mountains and other types of mountains
- D. To emphasize that hotspot volcanoes can produce large amounts of magma
- According to the crack hypothesis, what causes a hot spot?
- A. Hot magma rises from deep in Earth to melt a piece of the crust.
- B. Hot magma flows out through a break in the side of an active volcano.
- C. Hot magma flows up through spaces created between tectonic plates as they move.
- D. Hot magma flows up at a point where a tectonic plate has been stretched thin.
- What is the professor’s opinion of the two main hypotheses he presents?
- A. Neither hypothesis can explain the formation of the Hawaiian Islands.
- B. Each hypothesis accounts for some, but not all volcanic anomalies.
- C. Each hypothesis explains the formation of more volcanoes than plate tectonics does.
- D. The studies supporting the crack hypothesis are more convincing than those supporting the plume hypothesis.
C A C D D B