The correct answer to this open question is the following.
Although there are no options attached, or further context and references, we can say the following.
The ways in that the island of Madagascar is unique in the world is because Madagascar is an island in southeast Africa that is the home of some of the most unique and rare animals, plants, and vegetation on planet earth.
Explorers and scientists have found rare species of animals on the island such as the rare Lemurs, chameleons, and plants such as the baobab trees, orchards. Scientists say that 90% of these species are endemic, that is why the government is very strict in taking care of flora and fauna.