ZT-Earth Science: Extinction of large mammals

地球科学
Extinction of large mammals


1. What is the main purpose of the lecture?

  • A. To illustrate similarities between two periods of climate change
  • B. To examine theories about the extinction of large North American mammals 
  • C. To describe how scientists verify occurrences of meteor impacts on Earth 
  • D. To present a new explanation for the cause of the end of the last ice age 

2. What is the professor’s opinion of the claim that cooling during the Younger Dryas caused a major extinction?

  • A. It will probably be proven correct by future research
  • B. It has been strongly contradicted by recent soil-sample analysis 
  • C. It seems unlikely in view of what is known about similar climate changes 
  • D. It is based on a misinterpretation of evidence collected in North Americans 

3. Why does the professor mention a meteor that struck Earth during the time of the dinosaurs? 

  • A. To imply that that meteor impact also affect other large animals in North America
  • B. To point out that Earth was often struck by meteors in the past
  • C. To explain why it is to hypothesize that a similar impact could have caused a later extinction event 
  • D. To challenge a commonly accepted claim about dinosaur extinction 

4. According to the professor, what is the major significance of the Younger Dryas Boundary? 

  • A. It provides proof of a sudden climate change.
  • B. It lines the inside of a 13,000-year-old impact carter.
  • C. It contains valuable information on about the composition of meteors. 
  • D. It marks the disappearance of large mammal species. 

5. The professor mentions that a new group of researchers collected samples from a Younger Dryas Boundary site. How did those researchers explain the high concentration of magnetic particles in the samples?

  • A. The Younger Dryas Boundary is especially thick at that site. 
  • B. The particles were carried to the site by flowing water.
  • C. A meteor caused a high concentration of the particles at the site. 
  • D. Old roofing material had been buried at the site. 

6. What opinion does the professor express when he discusses nano diamonds? 

  • A. Their presence is not strong proof of a meteor impact
  • B. They indicate that a geological sample has been contaminated 
  • C. Researchers should get a better understanding of their origin 
  • D. Researchers should focus on magnetic particles instead of nano diamonds 

答案:
B C C D B A

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