2. Consumers: These are organisms that cannot make their own food and must eat other organisms to obtain energy. Consumers are classified into different trophic levels based on their position in the food chain. Primary consumers are herbivores that eat plants, secondary consumers are carnivores that eat primary consumers, and tertiary consumers are carnivores that eat secondary consumers.
3. Decomposers: These are organisms that break down dead plants and animals into simpler substances, releasing nutrients back into the environment. Decomposers include bacteria, fungi, and some invertebrates, such as worms and beetles.