Which trophies level is always a necessity in an energy pyramid or food chain

The lowest trophy level, also known as the primary producers, is always a necessity in an energy pyramid or food chain. These are the plants, algae, and other autotrophic organisms that convert sunlight or inorganic compounds into energy through the process of photosynthesis. They provide the foundational energy source for all other organisms in the food chain, thus making them essential in maintaining energy flow and sustenance for higher trophic levels.