The following organisms are consumers except

Analyze the question: We're asked which organism is NOT a consumer. Consumers are organisms that cannot make their own food and must feed on other organisms (heterotrophs).

Explain the concept:

• Producers (autotrophs): make their own food, usually by photosynthesis, using chlorophyll. Examples are green plants and algae.
• Consumers (heterotrophs): depend on other organisms for food. Examples are animals, fungi, and most bacteria.
• Saprophytes and decomposers, like fungi and many bacteria, are heterotrophs. They feed on dead organic matter, so they are grouped with consumers in a simple classification.

Step-by-step check of each option:

• A. Earthworm: an animal that feeds on decaying organic matter in soil. It is a consumer.
• B. Spirogyra: a green filamentous alga with spiral chloroplasts. It photosynthesizes, so it is a producer, not a consumer.
• C. Bacteria: most bacteria are heterotrophic (saprophytic or parasitic), so in this context they are consumers.
• D. Rhizopus: a fungus (bread mould) with no chlorophyll. It feeds saprophytically, so it is a consumer.

Answer: The only producer in the list is Spirogyra, so it is the exception.

Tip: In "consumer except" questions, look for the organism with chlorophyll. Algae like Spirogyra, Chlamydomonas and Spirulina, and green plants, are producers. Fungi (Rhizopus, Mucor, mushroom, yeast) and animals are never producers.