What is the term used to describe all animals that rely on plants, either directly or indirectly, for their food?

Consumers

The correct answer is Option (3) - consumers.

All animals that rely on plants, either directly or indirectly, for their food needs are classified as consumers. Consumers obtain their energy and nutrients by consuming other organisms, including plants or other animals in the food chain.

All animals that rely on plants for food — directly (herbivores) or indirectly (carnivores that eat herbivores) — are known as consumers in an ecological context.

• Producers = plants (make their own food via photosynthesis)
• Consumers = animals that eat plants or other animals
• Decomposers = break down dead organisms
• Grazers = a specific type of herbivorous consumer
• Root feeders = organisms that feed specifically on roots (not a broad category)

So, "Consumers" is the most comprehensive and correct answer.