Which of the following best defines a primary producer?

A primary producer is best defined as autotrophs that create energy from sunlight or chemicals. These organisms are crucial in ecosystems because they form the base of the food web. Primary producers, such as plants, algae, and certain bacteria, utilize processes like photosynthesis or chemosynthesis to convert inorganic substances into organic matter, effectively harnessing energy from their environment. This energy is then available to primary consumers, which rely on producers for their sustenance.

In contrast, organisms that consume other organisms would classify as consumers, not producers. Decomposers play a vital role in recycling nutrients back into the ecosystem by breaking down organic material, but they do not produce energy; rather, they help maintain nutrient cycling. Predators, while they help regulate populations of other species, also do not produce energy and instead feed on herbivores or other consumers. Therefore, the defining characteristic of primary producers lies in their ability to generate energy, marking their critical role in sustaining ecological systems.