Multiple choice

The length of the food chain in an ecosystem is generally limited to 3 - 4 trophic levels because

  1. quality of energy increases from lower to higher trophic levels

  2. quantity of energy decreases from lower to higher trophic levels

  3. quantity of energy increases from lower to higher trophic levels

  4. flow of energy is unidirectional

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Energy decreases at each trophic level due to inefficient energy transfer (approximately 10% efficiency), so higher trophic levels have progressively less energy available to support them. By the 3rd or 4th level, there's insufficient energy to sustain viable populations. Energy quality doesn't increase in a meaningful way, and while energy flow is unidirectional, that doesn't limit chain length - the quantitative energy loss does.

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