What are the throphic levels

Trophic levels have to do with food and the hierarchy of energy transimssion in food chains.

For instance, in a model food chain there is a Producer, which would always be an autotroph, meaning they produce their own food. Plants, some kinds of bacteria, algae etc.

Next come Consumers, that are heterotrophs, meaning they don't make their own food and so much acquire their energy by ingesting another lifeform.

Primary Consumers would be the next trophic level after Producers, they're the herbivores that eat consumers. For instance, a cow (Primary Consumer) that eats grass (Producer).

Secondary Consumers eat Primary Consumers. They're mostly carnivores or omnivores. For instance, humans (Secondary Consumer) eat a cow (Primary) that ate grass (Producer).

The three trophic levels of that food chain schematic would be

Producer -> Primary Consumer -> Secondary Consumer

It can go on, some food chains have Tertiary and even Quartenary Consumers.