Since what constitutes a proper diet remains a _______ subject on which few experts agree, additional research is
A) controversial required
B) neglected...deplored
C) popular...unexpected
D) favored...prohibited
E) complex...redundant

Question

Quizplus · Accepted Answer

A subject on which few experts agree cannot be described by the adjectives neglected, or popular, or favored. So, B, C and D can be ruled out on consideration of the choices for the first missing word. We cannot say that, on a complex subject on whom few experts agree, further research is redundant (meaning superfluous; not needed). So, E is also ruled out. A/ controversial subject is one on which few experts now agree, and therefore further research on it is required. Thus, A completes a meaningful sentence, and is the answer.

Since What Constitutes a Proper Diet Remains a _______ Subject