Forests are among the world's most valuable resources, both in a narro

Forests are among the world's most valuable resources,
both in a narrowly economic sense and in a broader,
ecological sense. Besides yielding over 5,000
commercial products that contribute some 2 percent to the
(5) world's total economic production, forests provide
recreation, reduce flooding, and prevent soil erosion
that clogs rivers with silt. However, if well-grounded
policy decisions are to be made concerning which
forests must be preserved and how much forest
(10) must be preserved, policy makers should have a
comprehensive understanding of the arguments for
and against the use of forests for economic gain. Two
claims often made—one about the oxygen-renewing
capacity of forests, the other about the role of forests
(15) in preserving biodiversity—merit special scrutiny.

Some consider the tropical rain forests of the
Brazilian Amazon region "the lungs of the earth,"
claiming that the foliage absorbs so much carbon
dioxide and produces so much oxygen that the
(20) atmosphere would be depleted of the latter if these
forests ceased to exist. But this belief is largely a
myth. Trees do produce oxygen by photosynthesis,
but when trees die, the decomposition process
consumes as much oxygen as the trees produced. In
(25) net terms, therefore, forests neither produce nor
consume oxygen.

Another claim made is that the preservation of
biodiversity, the globe's profusion of plant and animal
species, requires a stricter policy to conserve forest,
(30) especially tropical rain forest. For one thing, many
scientists believe that some tropical rain-forest plant
species yet to be discovered may contain agents with
unique disease-fighting properties. These plants can
offer crucial clues, as well as basic materials, for
(35) research on new medications. But even if one does
not think this indicates that biodiversity is a significant
resource, one could agree with the view, widely held
by some, that there is a moral imperative to preserve
species diversity—or, at least, that to do so would be
(40) a noninstrumental, that is, an intrinsic, good.

Actually, careful review of official statistics
suggests that tropical deforestation is not occurring as fast
as has often been claimed. Some existing forests,
however, do consist of commercial plantations, of
(45) which some people are highly critical. Such plantations
tend to contain significantly fewer plant and animal
species than natural forest. However, since plantations
are designed to produce large quantities of wood and
wood pulp, they reduce the economic pressure on true
(50) forests, increasing the latter's capacity to support
biodiversity. In addition, the size of such plantations is
often overstated by environmental activists. While the
World Wildlife Fund claims that plantations make up
"large tracts of current forest area," review of official
(55) data shows that plantations make up just 3
percent of the world's forest area.

1. Which one of the following most accurately states the main point of the passage?

(A) Arguments concerning the economic use of forests must be carefully examined before reasonable policy decisions can be made.
(B) The dangers posed to biodiversity by deforestation, although considerable, are insignificant when compared to those posed by ill-considered attempts at stricter regulation of forest usage.
(C) Careful review of official statistics shows that neither deforestation nor displacement of natural forest by commercial plantations is proceeding as rapidly as has been feared.
(D) While there is some hope that tropical rain forests might yield information that will result in new medicines, the primary reason for preserving them is their noninstrumental good.
(E) Assuming biodiversity is an instrumental good, imposing stricter regulation on the establishment of commercial plantations is an ineffective way to preserve such a good.


2. It can be inferred from the passage that many scientists believe which one of the following about rain-forest plants?

(A) Only a tiny proportion of rain-forest plant species actually have disease-fighting properties.
(B) Rain-forest plants are likely to produce medicines effective only against diseases that are endemic to tropical regions.
(C) The value of rain-forest plants derives in part from their providing basic materials for medical research.
(D) Rain-forest plants derive their medicinal properties from their capacity to absorb carbon dioxide and release oxygen.
(E) Rain-forest plants that have disease-fighting properties are almost completely extinct.


3. The information in the passage answers which one of the following questions?

(A) What percentage of the world's tropical rain forest is located in the Brazilian Amazon region?
(B) How many products are derived from plants grown on commercial plantations?
(C) By means of what process do plants produce oxygen?
(D) What measures, if any, could be taken to help existing forests produce more oxygen than they currently do?
(E) Do trees in tropical rain forests absorb more carbon dioxide than do other types of vegetation?


4. The stated relationship between the production of oxygen through photosynthesis and the consumption of oxygen in the process of tree decomposition (lines 22-26) is most analogous to which one of the following?

(A) Pay increases in a growing economy lead to increased purchasing power, but this increase is partially eroded through inflation if there is not a corresponding increase in productivity.
(B) Endangered species of plants are genetically modified in order to shorten their reproductive cycle as well as to enhance their resistance to natural parasites.
(C) Energy is expended in fertilizing and harvesting farm crops, but the cash return on the crops more than pays for the energy expended.
(D) An increase in the value of the shares of a company in a given production sector can spur an increase in the share values of other companies in that sector.
(E) Water evaporates from the ground during hot weather, and this water eventually condenses in the atmosphere and falls on the ground as rain or snow in the same region or elsewhere.


5. The author is primarily concerned with

(A) making policy proposals for the solution of a contemporary problem
(B) identifying and describing scientific solutions to contemporary environmental problems
(C) suggesting new ways in which an economic resource can be exploited
(D) mobilizing public support for the preservation of an important natural resource
(E) counterbalancing different points of view regarding an important topic being addressed by policy makers


6. Which one of the following statements about critics of commercial plantations is most consistent with the views of the author as expressed in the passage?

(A) Critics of commercial plantations should consider more carefully the relationships between commercial and noncommercial forests.
(B) Critics of commercial plantations do not recognize the medical potential of rain-forest plants.
(C) Critics of commercial plantations generally are well versed about photosynthesis and the effect on total biomass of a noncommercial forest.
(D) Critics of commercial plantations possess an adequate understanding of the economic and biological impact of restricting such enterprises.
(E) Critics of commercial plantations often demonstrate a broad understanding of global environmental issues.


7. Which one of the following statements is most strongly supported by the information in the passage?

(A) Some diseases that affect plants also affect human beings.
(B) Deforestation can have negative effects on water-based transportation.
(C) There are more commercial plantations than any other type of forest.
(D) There are more species of plants and animals internationally recognized as endangered in tropical rain forest than in nontropical forest.
(E) Commercial plantations produce goods that are rarely used in the countries where the plantations are located.