In the passage, the author is primarily interested in
(A) suggesting an alternative to an outdated
(B) introducing a new research method that calls an
accepted theory into question
(C) emphasizing the instability of data gathered
from the application of a new scientific method
(D) presenting a theory and describing a new
method to test that theory
(E) initiating a debate about a widely accepted
The author of the passage would be most likely to
agree with which of the following statements about the
(A) It is the only possible explanation for the ice
(B) It is too limited to provide a plausible explanation
for the ice ages, despite recent research
(C) It cannot be tested and confirmed until further
research on volcanic activity is done.
(D) It is one plausible explanation, though not the
only one, for the ice ages.
(E) It is not a plausible explanation for the ice ages,
although it has opened up promising possibilities
for future research.
Itcan be inferred from the passage that the isotope
record taken from ocean sediments would be less
usefulto researchers if which of the following were true?
(A) It indicated that lighter isotopes of oxygen
predominated at certain times.
(B) It had far more gaps in its sequence than the
record taken from rocks on land.
(C) It indicated that climate shifts did not occur
every 100,000 years.
(D) It indicated that the ratios of oxygen 16 and
oxygen 18 in ocean water were not consistent
with those found in fresh water.
(E) It stretched back for only a million years.
According to the passage, which of the following is
true of the ratios of oxygen isotopes in ocean
(A) They indicatethat sediments found during an ice
age contain more calcium carbonate than
sediments formed at other times.
(B) They are less reliablethan the evidence from
rocks on land in determining the volume of
(0 They can be used to deduce the relative volume
of land ice that was present when the sediment
was laid down.
(D) They are more unpredictable during an ice age
than in other climatic conditions.
(E) They can be used to determine atmospheric
conditions at various times inthe past.
It can be inferred from the passage that precipitation
formed from evaporated ocean water has
(A) the same isotopic ratio as ocean water
(B) less oxygen 18 than does ocean water
(C) less oxygen 18 than has the ice contained in
continental ice sheets
(D) a different isotopic composition than has
precipitation formed from water on land
(E) more oxygen 16 than has precipitation formed
from fresh water
Itcan be inferred from the passage that calcium
(A) are not as susceptible to deterioration as rocks
(B) are less common in sediments formed during an
(C) are found only in areas that were once covered
by land ice
(D) contain radioactive material that can be used to
determine a sediment's isotopic composition
(E) reflect the isotopic composition of the water at
the time the shells were formed