1. What does the professor mainly discuss?
- A. Processes that led bacteria to become trapped beneath a glacier.
- B. Bacteria that live in an environment that is inhospitable to most forms of life.
- C. The structural differences between bacteria and higher organisms.
- D. The different types of organisms that live near hydrothermal vents.
2. What does the professor say about bacteria that grow around hydrothermal vents?
[CHOOSE 2 ANSWERS]
- A. They are able to withstand higher temperatures than all other organisms.
- B. They are not as resilient as bacteria that live in glacial waters.
- C. They must have small amounts of sunlight to survive.
- D. They use hydrogen sulfide as their primary nutrient.
3. Why does the professor point out that the glacial pool has not frozen even though its temperature is below the freezing point?
- A. To point out that sulfate could not be recycled in water that has frozen.
- B. To emphasize that the pool is very salty.
- C. To point out that seawater is colder today than it was two million years ago.
- D. To imply that the amount of water in the pool has been slowly decreasing.
4. According to the professor, what is unique about the bacteria in the glacial pool that she discusses?
- A. The bacteria use sulfate to produce iron.
- B. The bacteria must have oxygen to survive.
- C. The bacteria convert sulfate to sulfite
- D. The bacteria use sulfide in reproduction.
5. What does the professor imply about iron in the glacial pool that she discusses?
- A. It is present in unusually low amounts for a glacial pool.
- B. It helps prevent the water in the pool from melting the glacier.
- C. It allows bacteria to maintain a constant supply of sulfate in the pool.
- D. It combines with excess oxygen in the pool.
6. Why does the professor say this?
- A. To signal that she is about to offer a contrasting way to consider bacteria.
- B. To imply that some types of bacteria have a more complicated structure than others.
- C. To encourage her students to point out interesting facts about bacteria to the class.
- D. To indicate that she agrees with the students’ opinion about bacteria.