Which of the following best describes a biotic factor?

A biotic factor refers to any living component that influences or interacts with the environment and other organisms. This includes various types of organisms such as plants, animals, fungi, and microbes, all of which play crucial roles in their ecosystems. For instance, plants provide oxygen and food, while predators influence prey populations, and decomposers break down organic matter, returning nutrients to the soil. Biotic factors are fundamental to the interactions within an ecosystem and contribute to its overall structure and function.

The other options describe abiotic factors or elements that do not involve living organisms. Physical components like rocks and soil, as well as climate, refer to the non-living parts of an ecosystem that can affect biotic factors. Meanwhile, chemical agents affecting animal life may involve interactions with living organisms but do not themselves qualify as biotic factors without living counterparts. Thus, the identification of a living organism that interacts with its environment as a biotic factor is accurate and reflects a foundational aspect of ecological study.