Question 23-33
The preservation of embryos and juveniles is rare occurrence
in the fossil record. The tiny, delicate skeletons are usually
scattered by scavengers or destroyed by weathering before
they can be fossilized. Ichthyosaurs had a higher chance of
being preserved than did terrestrial creatures because, as marine
animals, they tended to live in environments less subject to
erosion. Still, their fossilization required a suite of factors: a
slow rate of decay of soft tissues, little scavenging by other
animals, a lack if swift currents and waves to jumble and carry
away small bones, and fairly rapid burial. Given these factors,
some areas have become a treasury of well-preserved
ichthyosaur fossils.
The deposits at Holzmaden, Germany, present an
interesting case for analysis. The ichthyosaur remains are found in
black, bituminous marine shales deposited about 190 million
years ago. Over the years, thousands of specimens of marine
reptiles, fish, and invertebrates have been recovered from
these rocks. The quality of preservation is outstanding, but
what is even more impressive is the number of ichthyosaur
fossils containing preserved embryos. Ichthyosaurs with embryos
have been reported from 6 different levels of the shale in a
small area around Holzmaden, suggesting that a specific site
was used by large numbers of ichthyosaurs repeatedly over
time. The embryos are quite advanced in their physical develop-
ment; their paddles, for example, are already well formed.
One specimen is even preserved in the birth canal. In addition,
the shale contains the remains of many newborns that are
between 20 and 30 inches long.
Why are there so many pregnant females and young at
Holzmaden when they are so rare elsewhere? The quality of
preservation is almost unmatched, and quarry operations have
been carried out carefully with an awareness of the value of the
fossils. But these factors do not account for the interesting
question of how there came to be such a concentration of
pregnant ichthyosaurs in a particular place very close to their time
of giving birth.
23. The passage supports which of the following conclusions?
(A) Some species of ichthyosaurs decayed more rapidly than other species.
(B) Ichthyosaur newborns are smaller than other newborn marine reptiles.
(C) Ichthyosaurs were more advanced than terrestrial creatures.
(D) Ichthyosaurs may have gathered at Holzmaden to give birth.
24. The word "they" in line 4 refers to
(A) skeletons
(B) scavengers
(C) creatures
(D) environments
25. All of the following are mentioned as factors that encourage fossilization EXCEPT the
(A) speed of burial
(B) conditions of the water
(C) rate at which soft tissues decay
(D) cause of death of the animal.
26. Which of the following is true of the fossil deposits discussed in the passage?
(A) They include examples of newly discovered species.
(B) They contain large numbers of well-preserved specimens
(C) They are older than fossils found in other places
(D) They have been analyzed more carefully than other fossils.
27. The word "outstanding" in line 18 is closest in meaning to
(A) extensive
(B) surprising
(C) vertical
(D) excellent
28. The word "site" in line 22 is closest in meaning to
(A) example
(B) location
(C) development
(D) characteristic
29. Why does the author mention the specimen preserved in the birth canal (line 26)?
(A) To illustrate that the embryo fossils are quite advanced in their development
(B) To explain why the fossils are well preserved
(C) To indicate how the ichthyosaurs died
(D) To prove that ichthyosaurs are marine animals.
30. The word "they" in line 30 refers to
(A) pregnant females and young
(B) quarry operations
(C) the value of the fossils
(D) these factors
31.The phrase "account for" in line 33 is closest in meaning to
(A) record
(B) describe
(C) equal
(D) explain
32.Which of the following best expresses the relationship between the first and second paragraphs?
(A) The first paragraph describes a place while the second paragraph describes a field of study.
(B) The first paragraph defines the terms that are used in the second paragraph.
(C) The second paragraph describes a specific instance of the general topic discussed in the first paragraph.
(D) The second paragraph presents information that contrasts with the information given in the first paragraph.
33.Where in the passage does the author mentions the variety of fossils found at Holzmaden?
(A) Line 1
(B) Lines 3-5
(C) Lines 12-13
(D) Lines 19-21
Questions 34-41
The Lewis and Clark expedition, sponsored by President
Jefferson, was the most important official examination of the
high plains and the Northwest before the War of 1812. The
President's secretary, Captain Meriwether Lewis, had been
instructed to "explore the Missouri River, and such principal
streams of it as, by its course and communication with the
waters of the Pacific Ocean …may offer her most direct and
practicable water communication across the continent, for the
purposes of commerce." Captain William Clark, the younger
brother of famed George Rogers Clerk, was invited to share
the command of the exploring party.
Amid rumors that there were prehistoric mammoths
wandering around the unknown region and that somewhere in its
wilds was a mountain of rock salt 80 by 45 miles in extent,
the two captains set out. The date was May 14, 1804. Their
point of departure was the mouth of the Wood River, just
across the Mississippi from the entrance of the Missouri River.
After toiling up the Missouri all summer, the group wintered
near the Mandan villages in the center of what is now North
Dakota. Resuming their journey in the spring of 1805, the
men worked their way along the Missouri to its source and
then crossed the mountains of western Montana and Idaho.
Picking up a tributary of the Columbia River, they continued
westward until they reached the Pacific Ocean, where they
stayed until the following spring.
Lewis and Clark brought back much new information,
including the knowledge that the continent was wider than
originally supposed. More specifically, they learned a good deal
about river drainages and mountain barriers. They ended
speculation that an easy coast-to-coast route existed via the
Missouri-Columbia River systems, and their reports of the
climate, the animals and birds, the trees and plants, and the
Indians of the West – though not immediately published –
were made available to scientists.
34.With what topic is the passage primarily concerned?
(A) The river systems of portions of North America.
(B) Certain geological features to the North American continent.
(C) An exploratory trip sponsored by the United States government.
(D) The discovery of natural resources in the United States.
35.According to the passage, the primary purpose of finding a water route across the continent was to
(A) gain easy access to the gold and other riches of the Northwest
(B) become acquainted with the inhabitants of the West.
(C) investigate the possibility of improved farmland in the West.
(D) facilitate the movement of commerce across the continent
36.The river Meriwether Lewis was instructed to explore was the
(A) Wood
(B) Missouri
(C) Columbia
(D) Mississippi
37.According to the passage, the explorers spent their first winter in what would become
(A) North Dakota
(B) Missouri
(C) Montana
(D) Idaho
38.The author states that Lewis and Clark studied all of the following characteristics of the explored territories EXCEPT
(A) mineral deposits
(B) the weather
(C) animal life
(D) native vegetation
39.The phrase "Picking up" in line 23 could best be replaced by which of the following?
(A) Searching for
(B) Following
(C) Learning about
(D) Lifting
40.It can be inferred from the passage that prior to the Lewis and Clark expedition the size of the continent had been
(A) of little interest
(B) underestimated
(C) known to native inhabitants of the West
(D) unpublished but known to most scientists
41.Wherer in the passage does the author refer to the explorers' failure to find an easy passageway to the western part of the continent?
(A) Lines1-3
(B) Lines7-8
(C) Lines16-18
(D) Lines21-24
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