Identifying the Last Topic in a Lecture
During today's lecture on ecosystems, we will cover three main concepts. First, I will talk about the definition of an ecosystem. An ecosystem is a community of living organisms interacting with their environment. Next, we will explore the roles of different organisms in an ecosystem, including producers, consumers, and decomposers. Finally, we will discuss the impact of human activities on ecosystems, particularly how pollution and deforestation affect biodiversity.
Note: This question has been adapted from its original format to accommodate a reading-based version. In the official TOEFL exam, speaking and listening sections require verbal responses and audio prompts, which are not represented here. Please note that this adaptation may not fully reflect the nature or difficulty of the official exam. The audio feature for these sections will be available soon.