Official Explanation3. The author of the passage mentions “gastric atrophy” [Highlighted] primarily toMind-map- A particular medical phenomenon is introduced and explained
- A convenience that facilitates study into this phenomenon is explained
- A particular challenge involved in studying the long-term effects of this phenomenon is explained
A. Correct. The usage of the clause
“Most research on nutrient deficiencies involves relatively brief durations without the nutrient...” in conjunction with
“...the typical atrophy experienced by a B12-deficient patient may differ considerably from that produced by short-term deficiencies...” implies that most research into B12 deficiencies is limited, as the effects produced by short-term B12 deficiency differ from those produced by more sustained deficiency; the passage then cites
“gastric atrophy” as an effect that can be produced by even brief durations of B12 deficiency; hence, it can be inferred that the passage mentions
“gastric atrophy” to help demonstrate how the = information obtained through most research on B12 deficiency may not be enough to explain the effects of extended deficiencies. Simply put, as the mind-map indicates,
“gastric atrophy” is mentioned in the portion of the passage that explains a challenge in studying the long-term effects of B-12 deficiency.
B. Big Trap. The passage does not reference any research focused specifically on the short-term effects of B12 deficiency. Besides, as the mind-map indicates, the passage references
“gastric atrophy” as part of an explanation of how general research into B-12 deficiencies has not been able to explain the effects of long-term deficiencies. Incorrect.
C. Trap. The usage of the clause
“...durations of B12 deficiency can...impair...B12 absorption...” in conjunction with the phrase
“...a process known as ‘gastric atrophy’...” indicates that a subject experiencing an extended duration without vitamin B12 would likely experience gastric atrophy. Incorrect.
D. The usage of the clause
“...even short durations of B12 deficiency can briefly impair...B12 absorption...” in conjunction with the phrase
“...a process known as ‘gastric atrophy’...” implies that “gastric atrophy” can be caused by short-term B12 deficiencies; hence, it cannot be inferred that the mention of
“gastric atrophy” can qualify a claim about long-term B12 deficiencies. Incorrect.
E. The usage of the clause
“...durations of B12 deficiency can...impair...B12 absorption...” in conjunction with the phrase
“...a process known as ‘gastric atrophy’...” indicates that the passage mentions
“gastric atrophy” as an example of degradation in the body’s ability to absorb nutrients, rather than as part of an explanation of the underlying biological process. Incorrect.
Thus, A is the correct answer choice.