填空题
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 30million 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 15metres.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.