Question

1. through research has found that even the most ancient cultures) made music. the reasons behind its universal draw remain unexplained 2 however, until recently they have been unable to verify this theory 3 scientists have long assumed that there must be a neural basis for our love of music, and they have searched for evidence using conventional brain - scanning technology. 4 now, though, researchers at the massachusetts institute of technology (mit) have devised a weird trick for brain mapping that seems to support this long - held hypothesis. (13) these mit researchers performed mathematical analyses of scans of the auditory cortex and found that specific groups of neurons in this region, which is located in the temporal lobes, fires in response to music. however, they found a part of the brain that is dedicated to distinguishing music from other types of sound. during testing, neurons in the area fired in response to everything from bach to bluegrass and hip - hop but stayed unmoved by other sounds. different parts of the auditory cortex responded to such sounds as running water and falling trees. (16) after catalogued a library of easily recognizable sounds, the researchers scanned the brains of a num
2. which choice makes the sentence most grammatically acceptable?

a no change
b fire
c has fired
d is firing

Explanation:

The sentence structure requires a present - tense verb to describe the general action of neurons firing in response to music. The subject “specific groups of neurons” is plural. Option A is incorrect as the original form is wrong. Option C uses the present perfect “has fired” which is inappropriate for a general, ongoing action and also has a subject - verb agreement error (plural subject with “has”). Option D “is firing” is in the present continuous, which doesn't fit the context of a general action. So “fire” (Option B) is the correct choice as it is a plural - subject - agreeing, present - tense verb for a general action.

Answer:

B. fire