Answer:
Decomposer
Step-by-step explanation:
Food chain is mostly in the following order
Producer → Herbivore → Carnivore/Omnivore → Predators (owl)→ Decomposer
In the given food chain,
Raspberry bush is producer
Rabbit is herbivore
Owl can be considered as carnivore/omnivore/predator.
so, here decomposer is the missing level in the food chain.