Which of the following is an example of a biotic factor?

The correct answer, plant species, represents a biotic factor because it involves living organisms and their interactions within an ecosystem. Biotic factors include all the living components of an environment, such as plants, animals, fungi, and microorganisms. The presence and variety of plant species can significantly influence the characteristics of an environment and the organisms that inhabit it, as they provide food and habitat for a variety of species.

Water temperature, soil type, and sunlight availability are all examples of abiotic factors, which refer to the non-living components that influence an ecosystem. While these abiotic factors are crucial for determining the conditions and habitats suitable for living organisms, they are not considered biotic because they do not involve living entities. Understanding the distinction between biotic and abiotic factors is essential for studying ecosystems and their health, particularly in relation to water quality.