Question

an energy pyramid is shown.
which statement best describes the flow of energy through this pyramid?
a producers provide energy directly to the organisms in all the trophic levels above them.
b primary consumers transfer energy to the trophic level above them and the trophic level below them.
c secondary consumers represent the most organisms, and they have the greatest amount of energy in their trophic level.
d tertiary consumers do not receive all the energy from the trophic level below them, because some energy is lost to the environment.

Explanation:

• Option A is wrong: Producers (phytoplankton) only pass energy directly to the next trophic level (zooplankton), not all higher levels.
• Option B is wrong: Energy flows only upward in trophic levels; primary consumers (zooplankton) do not transfer energy back to producers below them.
• Option C is wrong: The lowest trophic level (producers, phytoplankton) has the most organisms and greatest energy, not secondary consumers (aquatic insects).
• Option D is correct: The 10% rule of energy transfer states only ~10% of energy moves to the next trophic level; most energy is lost as heat to the environment, so tertiary consumers (frogs) do not get all energy from the level below.

Answer:

D. Tertiary consumers do not receive all the energy from the trophic level below them, because some energy is lost to the environment.