1. What is the main purpose of the lecture?
- A. To explain how geologists determine the dates of ice ages
- B. To compare the geologic features of several different ice ages
- C. To discuss the possibility of a severe ice age during the Cryogenian period
- D. To examine the effects of a Cryogenian ice age on subsequent climate patterns
2. Why does the professor discuss the name of the Cryogenian period?
- A. To provide backgrounds for the basis of the Snowball Earth hypothesis
- B. To suggest that the Snowball Earth hypothesis is inappropriately named
- C. To contrast the Cryogenian period with later geologic periods
- D. To point out that the Cryogenian ice ages started in several different ways
3. According to the professor, what factors might have created the conditions for a snowball Earth event?
- A. A change in the proportion of land and wafer covering Earth’s surface
- B. The cooling effect of the oceans’ low surface albedo
- C. A change in the atmosphere that lowered Earth’s surface temperature
- D. A continuing cycle of radiation reflection and ice growth
4. Why does the professor talk about a research study in Oman?
- A. To illustrate why it is necessary to study evidence of glaciers from more than one location
- B. To determine how solar radiation affects glaciation
- C. To present evidence that Earth’s climate fluctuated during the Cryogenian period
- D. To explain why ice ages during the Cryogenian period differed from other ice ages
5. According to the professor, what is the chemical index of alteration used for?
- A. To describe changes in the chemical composition of the atmosphere
- B. To measure the degree of chemical weathering of rocks
- C. To find out how oceans affect global temperatures
- D. To trace the movement of rock over time
6. What is the professor’s opinion about the Snowball Earth hypothesis?
- A. Its basic premise is accurate and further study will validate it.
- B. It would be more plausible if the time frame were longer.
- C. It has some merit but a closer examination reveals flaws.
- D. It will probably never be completely discredited.
⬇️Go to the next Listening passage.