Increases in the level of high-density lipoprotein (HDL) in the human bloodstream lower bloodstream cholesterol levels by increasing the body's...
GMAT Critical Reasoning : (CR) Questions
Increases in the level of high-density lipoprotein (HDL) in the human bloodstream lower bloodstream cholesterol levels by increasing the body's capacity to rid itself of excess cholesterol. Levels of HDL in the bloodstream of some individuals are significantly increased by a program of regular exercise and weight reduction.
Which of the following can be correctly inferred from the statements above?
Passage Visualization
| Passage Statement | Visualization and Linkage |
|---|---|
| Increases in the level of high-density lipoprotein (HDL) in the human bloodstream lower bloodstream cholesterol levels by increasing the body's capacity to rid itself of excess cholesterol. |
Establishes: HDL → Cholesterol Reduction Mechanism Example Pattern:
Key Insight: HDL acts as cholesterol removal mechanism - higher HDL = better cholesterol elimination Mechanism: HDL ↑ → Body's cholesterol removal capacity ↑ → Blood cholesterol ↓ |
| Levels of HDL in the bloodstream of some individuals are significantly increased by a program of regular exercise and weight reduction. |
Establishes: Exercise + Weight Loss → HDL Increase (for some people) Example Pattern:
Key Limitation: Only works for "some individuals" - not universal Causal Chain: Exercise/Weight Loss → HDL ↑ (in some people) |
| Overall Implication |
Complete Causal Chain Established: Exercise/Diet → HDL ↑ → Cholesterol Removal ↑ → Blood Cholesterol ↓ Logical Bridge: The two statements create a connected pathway where lifestyle interventions can lead to cholesterol reduction through HDL improvement, but only for individuals who respond to exercise/diet with HDL increases. |
Valid Inferences
Inference: A program of regular exercise and weight reduction will lower bloodstream cholesterol levels for some individuals.
Supporting Logic: Since increases in HDL lower bloodstream cholesterol levels by increasing the body's capacity to rid itself of excess cholesterol, and since regular exercise and weight reduction significantly increase HDL levels in some individuals, therefore exercise and weight reduction will lower cholesterol levels for those individuals who experience HDL increases from such programs.
Clarification Note: This inference is limited to "some individuals" because the passage specifies that only some people experience significant HDL increases from exercise and weight reduction programs. The inference does not guarantee cholesterol reduction for all people who exercise and lose weight.
This choice makes an absolute claim about underweight individuals that goes far beyond what the passage tells us. The passage only discusses how HDL increases can lower cholesterol and how some people can increase HDL through exercise and weight reduction. It says nothing about underweight individuals or their cholesterol risk levels. We can't infer anything about weight categories and their associated cholesterol risks from this argument.
This creates a false dichotomy and makes predictions about future cholesterol risk that aren't supported by the passage. Just because exercise and weight reduction can increase HDL in some people doesn't mean that people who don't exercise regularly will definitely have high cholesterol risk. There could be many other factors affecting cholesterol levels that aren't mentioned in the passage.
This makes a comparative claim about effectiveness that we simply cannot make based on the given information. The passage tells us that exercise and weight reduction can increase HDL in some individuals, but it doesn't compare this approach to any other cholesterol-lowering methods. We have no basis for claiming these are the 'most effective' methods.
This follows perfectly from the logical chain established in the passage. We know that HDL increases lower cholesterol levels, and we know that exercise and weight reduction increase HDL levels in some individuals. Therefore, we can correctly infer that exercise and weight reduction will lower cholesterol levels in those same individuals who experience HDL increases. The qualifier 'some individuals' is essential and matches exactly what the passage supports.
This makes two problematic claims: first, that only exercise (not weight reduction) is necessary, and second, that this applies specifically to individuals of average weight. The passage mentions both exercise AND weight reduction as part of the program, and it doesn't distinguish between different weight categories. This choice contradicts the passage and makes unsupported assumptions.