Living Environment Regents Practice Test – Exam Prep & Study Guide

Symbiosis is best defined as a close relationship between two different species where at least one of the organisms benefits from the interaction. This definition encompasses a variety of interactions that can occur within ecological communities, such as mutualism, commensalism, and parasitism. In mutualism, both species benefit, while in commensalism, one species benefits and the other is neither helped nor harmed. In contrast, parasitism benefits one organism at the expense of the other. Understanding symbiosis is crucial as it highlights the interconnectedness of living organisms and the complex relationships that sustain ecosystems.