Scientists have discovered that our sense of smell is surprisingly _______ capable of distinguishing thousands of chemical odors
A) rigid
B) inert
C) erratic
D) keen
E) innate

Question

Quizplus · Accepted Answer

Obviously, the missing word must mean 'capable of distinguishing thousands of chemical odors'. Among the given choices, it is the word 'keen' which has this meaning. So, D is the answer.

Scientists Have Discovered That Our Sense of Smell Is Surprisingly