Answer and explanation

Correct answer: B. The number of organisms at each trophic level

  1. Step 1: A pyramid of numbers counts the individuals at each level of a food chain.
Answer
The number of organisms at each trophic level.
Why not the others: The energy at each level, The mass of the decomposers and The speed of energy transfer do not fit.

Practise more Human physiology and ecology.

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