CAT Critical Reasoning Practice question with Solution 76

Despite the fact that people suffering from acute W already have lower average blood-fat levels than the population at large, most doctors believe that reducing blood-fat levels is a good way to prevent acute W. This is an apparent paradox. The key lies in the relationship between low blood-fat levels and the disease. (C) says that a person can only contract acute W when the agent that causes acute W absorbs large quantities of fat from a person’s blood. This tells us two things: First, a person must have large quantities of fat in his bloodstream to contract acute W—this explains why reducing blood-fat is a good way to avoid contracting acute W. Second, people can only contract acute W after the agent has already absorbed a lot of blood fat—this explains why people who actually have acute W have low blood-fat levels. So (C) explains how both statements in the stimulus can be true, and thus resolves the paradox.

(A) is out of the scope, dealing as it does with people who have already been cured of acute W; (A) says nothing about why their blood-fat was low when they had acute W, or why people should reduce blood fat to keep from contracting the disease.

(B) contains a double scope shift: It points to a “synthetic fat substitute” (not fat), and says that animals who have been fed that substitute show “several symptoms” of acute W (not the disease itself). So the disease isn’t there, the fat isn’t there, and (B) isn’t anywhere.

(D) It’s hard to know what to make of (D); it doesn’t explain the correlation between low blood-fat and acute W, and certainly doesn’t explain how reducing blood-fat could prevent acute W—these people already have acute W.

(E) is also out of the scope. The stimulus is only interested in prevention of acute W, not in other diseases. (E) doesn’t address the paradox at all.