PrepTest 156 - Section 1 - Passage 4 - Question 23

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Discovered in 1993, the site known as Ukhaa Tolgod, in the Gobi desert of Mongolia, is one of the world's best sources of fossils from the Late Cretaceous period, which ended about 65 million years ago. ███ █████████ ███████ ███ ██████ ███████ ████ ████ █████ █████████ ████████ ██████████ ████ ████ █ ███████████ ███████ ███ ███████████████ ████ ██████████ ███

Phenomenon · Well preserved fossils

How did they form?

Hypothesis · Sandstorm buried the animals

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Hypothesis wrong · New evidence calls sandstorm hypothesis into question

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Details of Phenomenon · Three different types of sandstone at the site

1st Type · Well-defined structure

Consistent with sandstorm hypothesis...

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2nd Type · Tilt and layering

Also consistent with sandstorm hypothesis...

3rd Type · No layering; contains large pebbles

Inconsistent with sandstorm hypothesis because the pebbles are too large to have been windblown. This is the type that contains all of the vertebrate skeletal fossils.

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Alternate Hypothesis · Sand avalanche caused fossils

Avalanche trapped animals in its path, resulting in the pristine quality of the remains.

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Phenomenon · Avalanche / sandslides

What caused them?

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Hypothesis · Unclear; clay played a role

Unclear but likely clay and rain played a role.

Evidence · Modern sand dunes

Implications of hypothesis · Sandslide hypothesis suggests area was not sterile desert

Passage Style

Critique or debate

Phenomenon-hypothesis (RC)

23.

According to the passage, which ███ ██ ███ █████████ ███ ████ ██████████ ████████ ████ ███ ███████ █████ ██████████ █████████ ███ █████ ██ █████ ██████ ████ ██████ ██ ██████ ███████████

Question Type

Stated

The evidence that some have used to support the sandstorm hypothesis is described in P1: “The quality and completeness of their preservation was at first thought to have been due to immense, sudden sandstorms that buried the bodies of the animals before they could be scavenged or destroyed by exposure to the elements.” Nothing else is mentioned as support for the sandstorm hypothesis. So the correct answer should capture the quality and/or completeness of the fossils’ preservation.

the existence of █████ ████████ █████ ██ █████████ ██ █████ ██████

The author describes three types of sandstone in P2, but doesn’t suggest that the fact these three types exist at the site have been considered evidence supporting the sandstorm hypothesis.

the fact that ██████████ ███████ ██ ████ ██ █████ ███████ ███ ██ █████████ █████████

The author doesn’t mention unlayered sandstone in connection with support for the sandstorm hypothesis. It’s support for the sandslide hypothesis.

14%

the fact that █████ ████████ ██████████ ███████ ███ █████████ ████ █████████

Mentioned as a reason some supported the sandtorm hypothesis.

73%

the discovery of ████████ ██████████ ██ ███ ████ ██ █████████ ██ █████ ██████

Dinosaur footprints are mentioned in P2, but not in connection with evidence for the sandstorm hypothesis.

the fact that ████ █████████ ███ █████████ ██ ████ █████ ██ ████ ██████

Clay is mentioned in P4, but has nothing to do with evidence for the sandstorm hypothesis. It relates to the sandslide hypothesis.

PrepTest 156 - Section 1 - Passage 4 - Question 23

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