The Dutch cartographer, Abraham Ortelius, first suggested in 1596 that

The Dutch cartographer, Abraham Ortelius, first suggested in 1596 that the Americas were "torn away from Europe and Africa"; but there was little evidence to support his hypothesis. In England in 1620, Francis Bacon also noted that the similarity of many of the edges of various continents suggested that they once might have fit together like puzzle pieces. Evidence mounted gradually over the course of the next few centuries that continents were once joined: fossils of similar plant and animal species found on widely separated continents, long and linear zones of deformed rocks occurring at the edges of continents, and certain geologic and glacial features shared across different continents.

German meteorologist Alfred Wegener proposed in 1912 that the continents were all joined in a common landmass he named ―Pangaea‖, which began breaking up approximately 200 million years ago. In fact, precursors of this theory existed in maps depicting the joined continents, which had, it may be noted, been drawn almost a century earlier, but it was Wegener who was the first to combine the accumulating evidence for continental drift into a common framework—to weave seemingly dissimilar, unrelated facts into a theory. His proposal was not well received, however; it remained unclear how the continents actually moved, and science had not developed accurate radiometry to date the fossils or the linear belts of rock at the edges of continents. Geologist Arthur Holmes proposed in 1929 that the hot and melted rocks that made up the mantle of the Earth, the layer just beneath the Earth‘s thin crust, flowed upward, downward, and laterally, pushing apart regions of ocean floor or allowing nearby regions to collide and overrun each other; but again little evidence existed to support the idea. In the following decades, magnetic studies of the ocean floor, showing that the orientation of rocks had changed over the course of recent geologic time, helped confirm Holmes‘ ideas that ocean plates were the cause of the rifts and valleys on the ocean floor, as well as of the larger movement of landmasses.

By the early-1960s, a wealth of new evidence (much of it from studies of the ocean floor) formed a picture of what caused continents to drift. The sedimentary rocks of an oceanic origin were different from predial samples previously found, and geologists reasoned from this that continents were not simply upwellings of ocean floor. Continents are built of blocks of crust varying in age, size, rock composition, structure, and fossil assemblage (fauna and flora), with relatively stable, older interiors (the oldest rocks of which are more than 3 billion years old); the sea floors are significantly younger. The theory of mantle convection currents and sea-floor spreading became the prevailing explanation of how large plates of the Earth‘s crust continually move upward, downward, and to the side, allowing the separation of and collision of landmasses well above the moving ocean plates. In 1994, however, Seiya Uyeda concluded that subduction (the gravity-controlled sinking of a cold, denser oceanic slab into the subduction zone) ―plays a more fundamental role than seafloor spreading in shaping the earth's surface features" and "running the plate tectonic machinery." Current analysis of seismic waves and other geophysical studies continue to vastly expand our understanding of the Earth‘s interior and the components of plate tectonics theory.

1. The author most likely mentions the work of the Dutch cartographer Abraham Ortelius in order to:

A. show that the idea of plate tectonics is not new, although most evidence supporting it dates to the 20th century.
B. compare the state of Dutch and English cartography in the 16 th century.
C. draw a strong contrast between Ortelius‘ pioneering views and those of Wegener and Holmes.
D. show that cartography was sufficiently advanced in the 16 th century that predictions could be made about continental drift.
E. argue that plate tectonics is a recently developed concept

2. According to the author, the primary significance of the discovery that molten uprisings continually reshape the ocean floor is that:

A. these uprisings provide a mechanism for the continental drift that has clearly occurred.
B. it shows how sensitive the Earth‘s crust is to geologic activity taking place beneath it.
C. ocean floor movement lends strong support to the idea that the super-continent Pangea once existed.
D. the movement of deep ocean plates offers an explanation for magnetic and seismic measurements that have perplexed scientists for decades.
E. these help explain the phenomena of volcanic eruptions

3. What is the primary concern of the author in writing the passage?

A. to propose that modern maps are inaccurate compared to ancient maps
B. to discuss the gradual development and acceptance of the theory of plate tectonics.
C. to criticise the concept of Pangaea as proposed by some scientists.
D. to argue that all the continents will once again join together and become one
E. to explain that oceanic sedimentary rocks are different from those found on land

4. According to the passage, all of the following statements are true EXCEPT:

A. long, linear zones of rock on continental edges were recognized long before fossils on continental edges were accurately dated.
B. mantle convection currents help to explain seismic phenomena long measured by oceanographers and other studying continental drift.
C. fossils of similar plant and animal species can be found on widelyseparated continents only in the long, linear, coastal rock zones of those continents.
D. the Earth‘s crust is a thin, hard layer of solid rock, while the mantle is a molten, flowing sublayer of the crust.
E. Sea floors are younger than continental floors