Final answer:
Australia's flora and fauna are unique due to historical isolation, introduced species, biodiversity hotspots, and marsupial diversification.
Step-by-step explanation:
Australia stands apart from the rest of the world in terms of its flora and fauna due to several factors. Firstly, the historic isolation of Australia has allowed for the development of unique species that are not found anywhere else. This includes marsupials like kangaroos, wallabies, and koalas. Additionally, the introduction of new species through European colonization has given Australia a diverse range of organisms.
Another reason for the uniqueness of Australian flora and fauna is the country's status as a biodiversity hotspot, particularly in the southwest region. This area is rich in endemic plant species, although significant habitat loss has occurred due to agricultural development.
The absence of other mammals in Australia and the diversification of marsupials also contribute to its distinct fauna. Australia's long isolation and lack of migration opportunities have led to the evolution of new species that look different from their ancestors on the mainland.