We will answer and correct our study guide on Section 18.2, Ecology of Organisms, and then we will continue our ecological discussion that centers upon how energy is transferred among the living and nonliving components of the environment. We will emphasize the concepts of food chain and food web as we distinguish between them since they related to one another, and elaborate upon the role of the decomposers in the environment, i.e., niche, and examine why there are a few trophic levels in a typical ecosystem.