age contain more calcium carbonate than sediments
formed at other times.
(B) They are less reliable than the evidence from rocks
on land in determining the volume of land ice.
(C) 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 in the past.
5. 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
6. According to the passage, which of the following is (are)
true of the ice ages?
Ⅰ. The last ice age occurred about 25,000 years ago.
Ⅱ. Ice ages have lasted about 10,000 years for at least
the last several hundred thousand years.
Ⅲ. Ice ages have occurred about every 100,000 years
for at least the last several hundred thousand years.
(A) Ⅰ only
(B) Ⅱ only
(C) Ⅲ only
(D) Ⅰand only
(E) Ⅰ,Ⅱ and Ⅲ
7. It can be inferred from the passage that calcium
carbonate shells
(A) are not as susceptible to deterioration as rocks
(B) are less common in sediments formed during an ice