Question

The author of the passage is primarily concerned with

• A. confirming a theory
• B. supporting a statement
• C. presenting new information
• D. predicting future discoveries
• E. reconciling discrepant findings
• A. they failed to incorporate the most up-to-date information about the effect of clouds on climate
• B. they were based on faulty information about factors other than clouds that affect climate.
• C. they were based on different assumptions about the overall effects of clouds on climate
• D. their originators disagreed about the kinds of forecasts the models should provide
• J. their originators disagreed about the factors other than clouds that should be included in the models
• A. predict future changes in the world's climate
• B. predict the effects of cloud systems on the world's climate
• C. find a way to prevent a disastrous planetwide temperature increase
• D. assess the percentage of the Earth's surface covered by cloud systems
• O. estimate by how much the amount of carbon dioxide in the Earth's atmosphere will increase
• A. What kinds of cloud systems will form over the Earth?
• B. How can cloud systems be encouraged to form over the ocean?
• C. What are the causes of the projected planetwide temperature increase?
• D. What proportion of cloud systems are currently composed of cirrus clouds?
• T. What proportion of the clouds in the atmosphere form over land masses?

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
This question asks for the primary purpose of the passage as a whole. We need to analyze the structure and content to determine the author's main goal.
Step 2: Detailed Explanation:
Let's analyze the structure: - Paragraph 1: The author begins by stating a problem: as of the late 1980s, the effect of clouds on a warming globe was a major uncertainty. It presents two conflicting possibilities (stratocumulus clouds cooling vs. cirrus clouds warming).
- Paragraph 2: The author starts with the sentence, "That clouds represented the weakest element in climate models was illustrated by a study..." This sentence shows that the purpose of this paragraph is to provide evidence or illustration for the claim made at the end of the first paragraph and the beginning of the second. The paragraph then describes a study of 14 models that showed agreement without clouds but a "wide range of forecasts" when clouds were included, thus supporting the initial statement about uncertainty.
The author's primary purpose is to take the initial statement—that clouds are a major source of uncertainty in climate models—and support it with a specific example (the study of 14 models).
Let's evaluate the options:

(A) The author is not confirming a theory, but rather highlighting an area of uncertainty where theories conflicted.
(B) supporting a statement: This accurately describes the passage's structure. The author makes a statement ("clouds represented the weakest element") and then uses the rest of the passage to support it with evidence from a study.
(C) The information might be new to the reader, but the author's purpose is not just to present it, but to use it to support a point.
(D) The author is discussing the limitations of current prediction, not predicting future discoveries.
(E) The author is presenting discrepant findings, not reconciling them. The main point is that the discrepancies exist and are a problem.
Step 3: Final Answer:
The passage is primarily concerned with supporting the statement that clouds were the weakest, most uncertain element in climate models in the late 1980s.

Answer 2

Step 1: Understanding the Concept:
This is an inference question asking for the cause of the disagreement among the fourteen climate models. The passage states that the models disagreed when clouds were included, so the reason must be related to how clouds were modeled.
Step 2: Detailed Explanation:
The passage states that the models "agreed quite well if clouds were not included" (lines 14-15), but when "clouds were incorporated, a wide range of forecasts was produced" (lines 15-16). This tells us that the source of the disagreement lies in the way the models handled clouds.
The first paragraph gives a hint as to why this might be. It mentions that some studies suggested certain clouds (stratocumulus) would have a cooling effect, while other clouds (cirrus) would have a warming effect. This indicates that the overall effect of clouds is complex and depends on various factors.
If the 14 different models produced a "wide range" of results only when clouds were included, it is logical to infer that the models were built using different assumptions about how to represent these complex and conflicting effects of clouds. Some models might have assumed more of the cooling-type clouds, while others assumed more of the warming-type, leading to the wide range of forecasts. Let's evaluate the options:

(A) The passage states that as of the late 1980s, no one could "accurately predict" the effects of clouds. There was no single "up-to-date information" to incorporate; the problem was the lack of consensus.
(B) The passage explicitly states that the models "agreed quite well" on factors other than clouds, so this is incorrect.
(C) This is the most logical inference. The "wide range of forecasts" produced when clouds were included strongly suggests that the models were programmed with different underlying assumptions about the net effect of clouds on the climate.
(D) The passage discusses disagreement in the output (forecasts), not a disagreement about what kind of forecasts to provide.
(E) This is directly contradicted by the passage, which says the models agreed well when factors other than clouds were considered.
Step 3: Final Answer:
The disagreement among the models arose when clouds were included, strongly implying that the models were based on different assumptions about the complex effects of clouds on the climate.

Answer 3

Step 1: Understanding the Concept:
This question asks about the purpose of the climate models described in the passage. We need to identify what the models were trying to achieve, based on the description of the study.
Step 2: Detailed Explanation:
The second paragraph describes a study that compared "climate forecasts for a world with double the current amount of carbon dioxide." The passage then mentions that the discrepancies between the models meant that scientists could not easily "predict how quickly the world's climate would change," or which regions would face droughts or monsoons.
The language used—"forecasts," "predict," "climate would change"—all points to the general purpose of these models, which is to predict future climate changes. Let's evaluate the options:

(A) predict future changes in the world's climate: This is a general statement that accurately captures the function of "climate forecasts" and the goal of predicting changes like droughts and monsoons. This is the best answer.
(B) This is too specific. While the passage focuses on the difficulty of modeling clouds, the overall purpose of the models was to predict the climate as a whole, not just the effects of clouds. The clouds were one (problematic) component of a larger predictive effort.
(C) The models are tools for prediction, not for finding preventative measures. Their purpose is to forecast what will happen, not how to stop it.
(D) The models incorporate clouds, but their purpose is not stated to be assessing the percentage of cloud cover.
(E) The models seem to take a future CO2 level as an input ("a world with double the current amount of carbon dioxide"), rather than estimating the increase themselves.
Step 3: Final Answer:
The description of the models as producing "climate forecasts" and being used to "predict how quickly the world's climate would change" clearly indicates that their primary purpose was to predict future climate changes.

Answer 4

Step 1: Understanding the Concept:
This question asks what key information scientists are missing, according to the passage. The passage highlights a central uncertainty; we need to identify what question, if answered, would resolve that uncertainty.
Step 2: Detailed Explanation:
The first paragraph sets up the central problem. It states that some clouds (stratocumulus) could cause cooling, while other clouds (cirrus) could cause warming. The overall effect of clouds, therefore, depends on what \textit{kind} of clouds form in a warming world. If more stratocumulus clouds form, the effect might be cooling. If more cirrus clouds form, the effect will be warming.
The inability to predict the effect of clouds stems directly from this uncertainty about the type, and consequently the behavior, of future cloud systems. Therefore, to predict the overall effect, scientists would need to know what kinds of cloud systems will form. Let's evaluate the options:

(A) What kinds of cloud systems will form over the Earth?: This directly addresses the central uncertainty. Knowing the type of clouds that will form (cooling stratocumulus vs. warming cirrus) is the key to determining their net effect.
(B) The question is about predicting the effect, not encouraging a certain outcome.
(C) The cause of the temperature increase (implied to be carbon dioxide) is the premise of the problem, not the question that needs to be answered about clouds.
(D) The \textit{current} proportion of cirrus clouds is not as important as what the proportion will be in the \textit{future} as the climate changes. The problem is about predicting the change.
(E) The passage specifies stratocumulus clouds "over the ocean" but doesn't make a broader land vs. ocean distinction the central issue. The key issue is the type of cloud (cirrus vs. stratocumulus), not its location.
Step 3: Final Answer:
Since different kinds of clouds have opposite effects on global temperature, scientists must be able to determine what kinds of cloud systems will form in order to predict the overall impact of clouds.