Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute a food web.
Explanation: A food web is a network of interconnected food chains, where organisms at higher trophic levels eat organisms from lower trophic levels, allowing for diverse feeding relationships within an ecosystem.
Key points about the other options:
Ecological pyramid:
A graphical representation of the biomass or energy distribution at different trophic levels in an ecosystem.
Ecosystem:
A community of living organisms and their non-living environment interacting with each other.
Food chain:
A linear sequence of organisms where each one eats the one below it in the trophic hierarchy.