Answer:
Presence of 'Eucalyptus' tree species
Step-by-step explanation:
The koalas are commonly known as the koala beers. They are arboreal animals that belongs to the class of mammal known as the 'Mursupials', and they are herbivorous in nature and found to be dominantly present in the country of Australia.
The factor that allowed the population of koala to grow significantly beyond their habitat could sustain is the presence of 'Eucalyptus' tree species on which they are directly dependent on. This type of tree is commonly found in countries such as Australia and Tasmania, where the climate is suitable and there occurs sufficient amount of rainfall.