PrepTest 94+, Section 2, Question 14
When polar ice caps grow (during ice ages, for example), lighter forms of oxygen from water vapor and seawater accumulate in the frozen ice caps, leaving greater concentrations of one heavy form of oxygen behind in the sea, where it is absorbed by marine organisms. When and as the ice caps shrink, the concentrations of this heavy oxygen in seawater decrease. During one 30,000-year period, concentrations of this heavy oxygen in sea shellfish increased for about 20,000 years, then decreased for 10,000 years.
When polar ice caps grow (during ice ages, for example), lighter forms of oxygen from water vapor and seawater accumulate in the frozen ice caps, leaving greater concentrations of one heavy form of oxygen behind in the sea, where it is absorbed by marine organisms. When and as the ice caps shrink, the concentrations of this heavy oxygen in seawater decrease. During one 30,000-year period, concentrations of this heavy oxygen in sea shellfish increased for about 20,000 years, then decreased for 10,000 years.
When polar ice caps grow (during ice ages, for example), lighter forms of oxygen from water vapor and seawater accumulate in the frozen ice caps, leaving greater concentrations of one heavy form of oxygen behind in the sea, where it is absorbed by marine organisms. When and as the ice caps shrink, the concentrations of this heavy oxygen in seawater decrease. During one 30,000-year period, concentrations of this heavy oxygen in sea shellfish increased for about 20,000 years, then decreased for 10,000 years.
When polar ice caps grow (during ice ages, for example), lighter forms of oxygen from water vapor and seawater accumulate in the frozen ice caps, leaving greater concentrations of one heavy form of oxygen behind in the sea, where it is absorbed by marine organisms. When and as the ice caps shrink, the concentrations of this heavy oxygen in seawater decrease. During one 30,000-year period, concentrations of this heavy oxygen in sea shellfish increased for about 20,000 years, then decreased for 10,000 years.
The information given most strongly supports which one of the following hypotheses about the period described above?
Average global temperatures 10,000 years after the beginning of the period approximately equaled average global temperatures 20,000 years later.
Polar ice caps at the beginning of the period were larger than they were at the end of the period.
The beginning of the period coincided with the onset of an ice age that lasted approximately 20,000 years.
The polar ice caps grew for about 20,000 years after the period began, then began to shrink.
An ice age was drawing to an end during the first 20,000 years of the period.
0 Comments