The Antarctic is the most remote continent and the last to be discovered, but it constitutes up about a tenth of the 【M1】______ world's land surface. It is also the only continent without an indigenous human people. 【M2】______ In the past it had a warm climate, supporting luxury 【M3】______ vegetation and large animals, but the climate deteriorated over the last 30 million years. Once a great continent 【M4】______ Gondwana had drifted apart sufficiently for a southern circumpolar current to become established. This, the largest ocean current in the world, cut off Antarctica from the warmer oceans to the north and 'allowed the ice sheets in places over four kilometers high, to develop. 【M5】______ This region is the earth's major heat sink and contains ninety percent of the world's ice and nearly three-quarters of its water. Only two percent of the continent is not covered 【M6】______ by ice, and the life retains a tenuous foothold there. Nearly the half of Antarctica's coastline is hidden by 【M7】______ thick float ice shelves or glacier, and the rest is scoured 【M8】______ by icebergs down to depths of 15 metres. But below this level there is a colorful marine world containing a great diverse 【M9】______ of life. Recent work has shown that the pack ice supplies a surprising rich Winter habitat 【M10】______ for a number of small creatures. 【M1】