Final answer:
To separate the coordinate adjectives in the given sentence, insert a comma after the first adjective.
Step-by-step explanation:
To separate the coordinate adjectives in the given sentence, you should insert a comma after the first adjective. So, the correct sentence would be: Considered both a continent and a country, Australia is home to numerous native species of plants and animals. Incredibly, more than eighty percent of these remarkable unique inhabitants are found solely in Australia.
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