Answer:
a. True
Step-by-step explanation:
Energy pyramids are a simple representation of the flow of energy at each trophic level in an ecosystem, based on the well known fact that a lot of energy gets lost between consumers (approximately only around 10% is made into tissues, while 90% is used up and is lost as heat).
While the biomass and abundance of the organisms at a trophic level, even the identity of that organisms (species), is highly dependent on the characteristic of the environment. So very different environments (for example, a dessert and a rain forest) will have also very different species with different biomass and abundance fulfilling the same trophic role.