What destroyed the civilisation of Easter Island?

Complete the summary. Write ONE WORD ONLY from the text in each gap. 

Jared Diamond’s View

Diamond believes that the Polynesian settlers on Rapa Nui destroyed its forests, cutting down its trees for fuel and clearing land for 8. . Twentieth-century discoveries of pollen prove that Rapa Nui had once been covered in palm forests, which had turned into grassland by the time the Europeans arrived on the island. When the islanders were no longer able to build the 9. they needed to go fishing, they began using the island’s 10. as a food source, according to Diamond. Diamond also claims that the moai were built to show the power of the island’s chieftains, and that the methods of transporting the statues needed not only a great number of people, but also a great deal of 11. .