Practice Test: Reading Comprehension - 82 | 100 RCs for GMAT PDF Download

The author describes a method for determining past climatic conditions and then offers specific examples of situations in which it has been used.

The author discusses the method of dating marine and continental sequences and then explains how dating is more difficult with lake levels than with pollen profiles.

The author describes the common requirements of methods for determining past climatic conditions and then discusses examples of such methods.

The author describes various ways of choosing a material for determining past climatic conditions and then discusses how two such methods have yielded contradictory data.

The author describes how methods for determining past climatic conditions were first developed and then describes two of the earliest known methods.

The kinds of plants normally found in arid regions

The effect of variation in lake levels on pollen distribution

The material best suited to preserving signals of climatic changes

Other criteria invoked by paleoclimatologists when choosing a method to determine past climatic conditions

A third method for investigating past climatic conditions

had to be interpreted by modern chemical means

reflected a change in climate rather than a long-term climatic condition

was incorporated into a material as the material was forming

also reflected subsequent environmental changes

was contained in a continental rather than a marine sequence

It is sometimes more difficult to determine past climatic conditions in arid and semiarid regions than in temperate regions.

Although in the past more research has been done on temperate regions, paleoclimatologists have recently turned their attention to arid and semiarid regions.

Although more information about past climates can be gathered in arid and semiarid than in temperate regions, dating this information is more difficult.

It is difficult to study the climatic history of arid and semiarid regions because their climates have tended to vary more than those of temperate regions.

The study of past climates in arid and semiarid regions has been neglected because temperate regions support a greater variety of plant and animal life.

Data provided by dating marine sedimentation is more consistent with researchers’ findings in other disciplines than is data provided by dating continental sedimentation.

It is easier to estimate the age of a layer in a sequence of continental sedimentation than it is to estimate the age of a layer in a sequence of marine sedimentation.

Marine sedimentation is much less widespread than continental sedimentation.

Researchers are more often forced to rely on extrapolation when dating a layer of marine sedimentation than when dating a layer of continental sedimentation.

Marine sedimentation is much more continuous than is continental sedimentation

There is usually more precipitation during an ice age because of increased amounts of evaporation.

There was less precipitation during the last ice age than there is today.

Lake levels in the semiarid southwestern United States were lower during the last ice age than they are today.

During the last ice age, cooler weather led to lower lake levels than paleoclimatologists had previously assumed.

The high lake levels during the last ice age may have been a result of less evaporation rather than more precipitation.

illustrate the mechanics of the relationship between lake level, evaporation, and precipitation

provide an example of the uncertainty involved in interpreting lake levels

prove that there are not enough ancient lakes with which to make accurate correlations

explain the effects of increased rates of evaporation on levels of precipitation

suggest that snow-line elevations are invariably more accurate than lake levels in determining rates of precipitation at various points in the past

I only

II only

I and II only

I and III only

II and III only