Read the following statements regarding ecological pyramids and choose the correct answer.
a. The relationship between organisms at different trophic levels is expressed in terms of number, biomass and energy.
b. Any calculations of energy content, biomass or number has to include one group of the organism at that trophic level.
c. In most ecosystems, all the pyramids of number, biomass and energy are upright.
d. The pyramid of biomass in the sea is generally inverted.
e. Pyramid of energy is always inverted and can never be upright.