Question

which of these is an abiotic (non-living) part of a food chain?
the sun
the producers
primary consumers

Explanation:

Abiotic factors are non - living components of an ecosystem (and food chain). The sun is a non - living entity that provides energy for the food chain. Producers (like plants) and primary consumers (like herbivores) are living (biotic) components as they are organisms.

Answer:

the sun