Complex sentence: Presently, Arago and the Macdonald hotspot are the two active hotspots of the Austral Islands, but a hotspot that formed Rarotonga may also be active still; additional hotspots in the area are Tubuai, Taukina and Ngatemato.
Split into simpler sentences: Presently, Arago and the Macdonald hotspot are the two active hotspots of the Austral Islands. A hotspot that formed Rarotonga may also be active still; additional hotspots in the area are Tubuai, Taukina and Ngatemato.