Which of the following best describes an organism?

An organism is defined as any living entity that exhibits vital processes essential for life, including those found in plants, animals, and fungi. This definition encompasses a wide variety of life forms that are characterized by their ability to grow, reproduce, respond to stimuli, and maintain homeostasis.

Focusing on the specifics of the correct choice, it highlights the diversity of life by recognizing not just animals, but also plants and fungi as organisms. Each of these groups plays a crucial role in ecosystems, contributing to processes such as nutrient cycling and energy flow.

In contrast, non-living chemical compounds do not exhibit any of the characteristics associated with life, such as metabolism or reproduction, and thus do not qualify as organisms. The option that mentions only plants that photosynthesize is overly restrictive, as it excludes animals and fungi, which are equally vital to the definition of an organism. Lastly, describing a pesticide as an organism is inaccurate, as pesticides are substances used to control or eliminate pests rather than living entities themselves.