In an ecological pyramid, which trophic level is represented at the base?

Producers

The correct answer is Option (4) - Producers.

In an ecological pyramid, the trophic level represented at the base is the producers. Producers, also known as autotrophs, are organisms that can convert sunlight energy into chemical energy through the process of photosynthesis. They are typically green plants, algae, or certain types of bacteria.

Producers occupy the first trophic level in an ecosystem because they are capable of producing their own food using energy from the sun. They form the foundation of the food chain by converting solar energy into organic matter, such as glucose, which serves as a source of energy and nutrients for other organisms.

Above the producers are the primary consumers (option c), which are herbivores that feed directly on the producers. Primary consumers obtain their energy by consuming plant material or algae. Secondary consumers (option b) are the carnivores that feed on the primary consumers, and tertiary consumers (option a) are carnivores that feed on other carnivores.

The ecological pyramid represents the flow of energy, biomass, or number of individuals at each trophic level in an ecosystem. It typically takes the shape of a pyramid, with the producers forming the broad base, followed by the successive trophic levels narrowing towards the apex.