Nhận biết (M1)

Text 1

Uisdean Nicholson and his team have discovered evidence in seismic data of a 40-kilometer-wide

subsurface crater beneath nearly a kilometer of water off the coast of West Africa that is consistent with a

400-meter-wide asteroid striking the seafloor. This structure, which the team named Nadir, exhibits all the

telltale signs of a high-velocity impact crater: an elevated rim, a circular shape, a terraced floor, and a

pronounced area of uplift at its center.

Text 2

Both carbonate dissolution and subsurface salt withdrawal can cause craterlike depressions without the

need for a high-velocity impact. However, carbonate dissolution is very unlikely to have occurred in the

vicinity of Nadir, and although subsurface salt withdrawal could have plausibly occurred in this area and

would result in a depression with a terraced floor or a circular shape, it would not exhibit the area of

central uplift seen at Nadir

Which choice best describes a difference between the approach of Text 1 and the approach of Text 2?

• A.

  Text 1 dispassionately describes Nicholson and colleagues’ findings and conclusions, whereas Text 2

• B.

  Text 1 focuses on features Nadir lacks, whereas Text 2 indicates features it shares with other

• C.

  Text 1 emphasizes the evidence supporting an asteroid impact as the cause of Nadir, whereas Text 2

• D.

  Text 1 discusses a single plausible cause of Nadir, whereas Text 2 evaluates two possible causes.