Except perhaps for some remote island dwellers, most people have a natural tendency to view continents as fundamental, permanent and even characteristic features of Earth. One easily forgets that the world’s continental platforms amount only to scattered and isolated masses on a planet that is largely covered by water. But when viewed from space, the correct picture of Earth becomes immediately clear. It is a blue planet. From this perspective it seems quite extraordinary that over its long history, Earth could manage to hold a small fraction of its surface always above the sea — enabling, among other things, human evolution to proceed on dry land. Is the persistence of high-standing continents just an accident? How did Earth’s complicated crust come into existence? Has it been there all the time, like some primeval icing on a planetary cake, or has it evolved through the ages? Such questions engendered debates that divided scientists for many decades, but the fascinating story of how the terrestrial surface came to take its present form is now partly resolved. That understanding shows, remarkably enough, that the conditions required to form the continents of Earth may be unmatched in the rest of the solar system.
One important point made in the passage is that ____.
new questions concerning the solar system are constantly coming to the fore
scientists have finally been able to understand fully the mystery of Earth’s crust
people living on remote islands are so cut off from the rest of the world that they have no idea about what is happening elsewhere
the formation of the continents of Earth may have no parallel elsewhere in the solar system
the growing pollution of the oceans is causing a great deal of concern among scientists
According to the passage, the question of how Earth’s continents came into being ____.
has never attracted much attention
has been one of the concerns of space research and exploration
can best be answered through a comprehensive study of the other planets in the solar system
is not likely to be resolved in the near future
gave rise to considerable disagreement among scientists
The passage calls Earth the “blue planet” to underline the fact that ____.
the waters of the oceans are crystal clear
the geographical features of Earth are not very distinct when viewed from space
many things on Earth are blue
there is actually very little land on Earth
it is man’s duty to keep the seas clean
The passage suggests that the inhabitants of small isolated islands ____.
will be adversely affected if the oceans continue to be polluted
have frequently chosen to live in comparative isolation in preference to living in a crowded city
always demonstrate a keen interest in the solar system
depend for their living more on the sea than on the land
probably have a better perception of the reality of Earth than the majority of us