Organisms that directly feed on producers are known as __________.

The correct answer is: Primary Consumers

Predators are organisms at the top of the food chain who have no predators of their own.
Producers are at the beginning of the food chain as they produce food for the entire food chain. Herbivores feed on producers.
Decomposers decompose dead and decaying organic matter.
Tertiary consumers feed on secondary consumers.
Hence, primary consumers is the correct answer.