Tertiary level where the top most carnivore is placed.
reason :
In an ecological pyramid, the primary producer (trees or species containing chlorophyll) capture the maximum sunlight in the pyramid to produce food. Primary producer lie at the base of the pyramid and lets assume that it has 100% of energy within it. Now as we move upward, to the next level i.e primary consumer level , only 10% of energy is passed to this level and 90 % energy is retained at previous level. The tertiary level species lies at the top and 10 % of the total energy of its previous level is only transferred to it. Thus, the least usable energy shall be retained at the tertiary level of ecological pyramid.
