Answer:
niche specialist is the correct answer.
Step-by-step explanation:
This is an example of a niche specialist because the niche specialist species are specialized to survive in a particular environment and they need specific resources and also they feed on particular species.
Koalas survive by feeding on eucalyptus leaves and these eucalyptus leaves are very poisonous to other animals.
To cope with this diet, nature has provided koalas by specific adaptations.