Part 1: Food chains and food webs
Food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats the other. Producers → Primary consumers → Secondary consumers Food webs are interconnecting food chains that actually exist in an ecosystem.
Part 2: Humans in a food chain and food web
Humans can consume both plants and animals and thus they can occupy any of the three levels. They can be primary consumers when they eat plants, secondary consumers as well as tertiary consumers when they eat meat.