which tropic level is always a necessity in an energy pyrite or food energy

secondary consumer

primary consumer
producer
tertiary consumer

The producer is always a necessity in an energy pyramid or food chain. Producers, also known as autotrophs, are able to convert sunlight or inorganic compounds into usable energy through the process of photosynthesis. They serve as the base of the food chain, as they provide energy and nutrients for all other trophic levels.