Answer: primary.
- A primary
- B secondary
- C tertiary
- D zero
Correct answer: A. primary
Explanation: Primary productivity is the rate at which producers make organic matter.
Energy pyramid showing a simple food chain (producer to herbivore to carnivore) with energy decreasing roughly tenfold at each trophic level.
Concept context
Ecosystems, food chains, energy flow, nutrient cycles, biodiversity, and conservation.