Half of the subjects in an experiment – the experimental group – consumed large quantities of a popular artificial sweetener. Afterward, this group showed lower cognitive abilities than did the other half of the subjects – the control group – who did not consume the sweetener. The detrimental effects were attributed to an amino acid that is one of the sweetener’s principal constituents.
Which of the following, if true, would best help explain how the sweetener might produce the observed effect

Question

Examsnet · Accepted Answer

Correct Answer is :  A high level of the amino acid in the blood inhibits the synthesis of a substance required for normal brain functioning.

GMAT Verbal Reasoning Practice Test 5