The secular cooling that must someday overtake our planet has already gone far indeed with our neighbour. Its physical condition is still largely a mystery, but we
know now that even in its equatorial region the midday temperature barely
approaches that of our coldest winter. Its air is much more attenuated than ours, its
oceans have shrunk until they cover but a third of its surface, and as its slow season
change hugg snowcaps gather and melt about either pole and periodically inundate
its temperate zones. That last stage of exhaustion, which to us is still incredibly
remote, has become a present-day problem for the inhabitants of Mars.
Which of the following details comes from supporting evidence? (5 points)