because groundbreaking refers to something completely new that before did not exists.

His work instead was an innovation that led to improvement even though they are light years ahead of the knowledge of before.

E is the answer

Dr. Kim’s innovative work with epithelial cell lines (i) _______ the field of immunology; prior to her (ii) _______discoveries, no one had ever isolated those pivotal genes, much less generated a functional mouse model.


Dr. Kim's work has done something "innovative" in the field of immunology. This sounds that her work has been precursor in her field. And, that has "revolutionized" the field.

Prior to her work, no one has ever figured this stuff out. So, the second blank must be along the similar lines of "revolutionary". Only groundbreaking can fit in the second column.

Dr Kim's work has revolutionized the field of immunology, because prior to her groundbreaking discovery, no one had any clue to generate a functional mouse model.

The two parts of sentence are divided by ; so blank ii and i should both be either positive or negative. Now looking at third part of sentence "no one had ever isolated those pivotal genes, much less generated a functional mouse model" , we know that it is positive. So now looking at blank ii it gives us the clue that the discovery is a innovative, first time and path breaking discovery. Looking at option we get ground breaking as best option. innocuous means harmless and does not fit the blank. Prototype mean a basic version or preliminary version which also does not fit teh word we are looking for.

Next we are again looking for a word such as changed or boost for blank i , among the three words only revolutionized fits closely to our estimated words.

This has been tagged in hard, I would suggest to move it to Easy-Medium considering the % of the people who got it right; Also, it's a pretty straight-up question

The sentence word prior suggest that the work done by Mr.Kim is unprecendented and is of more significance than his predecessors .So groundbreaking fits well for the second blank
Innovative suggest that the first blank should be a positive word that brought about change in research so revolutionized is apt


PLEASE GIVE KUDO's IF YOU LIKE THE EXPLANATION.I'M WILLING TO THE PRACTICE TESTS.

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