环境科学
TPO52-L2 Interactions within an Ecosystem
Listen to part of a lecture in an environmental science class.
- What is the lecture mainly about?
- A. A new approach to ensuring the survival of a forest ecosystem
- B. Similarities between desert and forest-stream ecosystems
- C. Interactions that take place within a North American forest ecosystem
- D. Factors that have contributed to the preservation of salmon populations in forest ecosystems
- Why does the professor mention ants and rodents competing for food?
- A. To make sure the students understand the different components of an ecosystem
- B. To point out the limited resources available to organisms in a desert ecosystem
- C. To illustrate how different species adapt to extreme temperatures
- D. To provide an example of an easily understood interaction within an ecosystem
- According to the professor, how do trees contribute to the successful spawning of salmon?
[CHOOSE 2 ANSWERS]
- A. They provide streams with nutrients that the salmon need.
- B. They provide shade that keeps streams sufficiently cool.
- C. They help salmon avoid predators by providing camouflage.
- D. They reduce the amount of sediment entering streambeds.
- What point does the professor make about bears carrying salmon away from streams?
- A. It results in bears eating fewer fish.
- B. It reduces the amount of food available to scavengers.
- C. It improves the health of the surrounding trees.
- D. It improves the water quality of the streams.
- What does the professor imply about overfishing?
- A. It is one of several reasons that the bear population has declined.
- B. It is difficult to prevent in both oceans and streams.
- C. It cannot be the sole focus for those working to prevent salmon depletion.
- D. Its impact is minor compared to the problems caused by logging.
- Why does one of the students say this: 🎧
- A. To provide support for a hypothesis mentioned by the professor
- B. To suggest that a bear behavior mentioned by the professor seems improbable
- C. To explain why confrontations take place between bears
- D. To explain why bears eat so much in a short time span
答案：
C D BD C C B