Answer and Explanation:
a. Primary producers
Primary producers are organisms that are able to produce their own food, also known as autotrophs. The best example to illustrate this group are <em>plants</em>. <u>They have a major role in the carbon cycle as they transform inorganic molecules from the atmosphere, such as CO2, into organic molecules like carbohydrates.</u>
b. Secondary producers
Secondary producers are organisms that feed on primary producers, that is, they are heterotrophs (and herbivores), which are then consumed by predators. For example, caterpillars or rabbits. <u>When these organisms respirate, they exhale carbon dioxide, which is used by primary producers in the carbon cycle.</u>
c. Decomposers
Decomposers are organisms that consume and break down organic matter such as dead animals, feces, and leaves. For example, fungi and bacteria. <u>Through this process, they release CO2 and methane into the atmosphere, making carbon dioxide available for plants to carry out photosynthesis.</u>