Biology CLEP Prep Practice Exam

An ecosystem is a system or community that consists of all living and nonliving things in a particular area and their interactions. While choices A, B, and C all involve interactions, they are not an accurate representation of what an ecosystem is. Choice A focuses only on one species, while choice B focuses on multiple species without mentioning other components of an ecosystem such as abiotic factors. Choice C also only describes the interactions of a single organism, rather than all living things in an area. Choice D, however, acknowledges the importance of the interactions between a population of species and the environment they live in, making it the correct answer.