1. What does the professor mainly discuss?
- A. A theory about the breakup of the Gondwana supercontinent during the Cambrian period.
- B. A possible relationship between plate tectonics and the relatively sudden appearance of complex life on Earth.
- C. How a massive mountain range might have affected climate during the Cambrian period.
- D. A new tool developed by Australian researchers to analyze fossils found in ancient seabeds.
2. Why does the professor mention the fossil record?
- A. To provide background for a topic he wants to discuss.
- B. To suggest that a geologic time period may have been inaccurately estimated.
- C. To make a distinction between speculation and hypothesis.
- D. To give an overview about how shelled animals become fossilized.
3. What is the professor’s attitude toward the Gondwana super mountain hypothesis?
- A. He considers it a reasonable explanation.
- B. He is surprised that no one propose it earlier.
- C. He understands why it is controversial.
- D. He suspects that it will be replaced by a better hypothesis.
4. According to the professor, what caused the Gondwana super mountain to form?
- A. A partial breakup of Gondwana.
- B. The drift of Gondwana toward the equator.
- C. The crash of two huge mountain ranges near India.
- D. A merging of continents in the Southern Hemisphere.
5. What does the professor imply about algae?
- A. Some species of algae evolved to survive on dry land.
- B. Some species of algae became extinct at the end of the Cambrian period.
- C. Algae brought nutrients into the food chain during the Cambrian period.
- D. Algae probably did not exist before the Cambrian period.
6. What did researchers determine about the zircon in the sandstone samples that they studied?
- A. Zircon tends to decrease the rate at which sandstone weathers.
- B. Zircon was unusually abundant in sandstones from the Gondwana supercontinent.
- C. Zircon in sandstone from Australia is as old as the Himalayas.
- D. Zircon of the same age is found in sandstone samples from different continents.