Which of the following organisms is a primary consumer?

Step 1: Analyze the question We need to identify which organism is a primary consumer, meaning an organism in the second trophic level of a food chain.

Step 2: Explain the concept In a food chain, energy flows through these levels:

• Producers: make their own food by photosynthesis (green plants, e.g. grass)
• Primary consumers: feed directly on producers (herbivores)
• Secondary consumers: feed on primary consumers (carnivores or omnivores)
• Decomposers: break down dead organic matter (fungi, bacteria)

Food chain example: Grass → Sheep → Dog/Man

Step 3: Evaluate each option

• A. Dog: It eats meat, and often other foods too. It is a secondary consumer (carnivore or omnivore), not a primary one.
• B. Sheep: It feeds directly on grass, so it is a herbivore and a primary consumer. ✔
• C. Grass: It makes its own food by photosynthesis, so it is a producer.
• D. Fungus: It feeds on dead or decaying matter, so it is a decomposer (saprophyte).

Step 4: Answer The correct answer is B. Sheep.

Exam tip: "Primary" means "first" consumer, the first one to eat the producer. Ask yourself: "Does it eat plants directly?" If yes, it is a primary consumer. Typical examples are goat, cow, grasshopper, rabbit, and sheep.