ZT-Geology: Cambrian Explosion

地质学 地球科学
Cambrian Explosion


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.

答案:B A A D C D

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