nightblade354 wrote:
Each of many different human hormones can by itself raise the concentration of glucose in the blood. The reason for this is probably a metabolic quirk of the brain. To see this, consider that although most human cells can produce energy from fats and proteins, brain cells can use only glucose. Thus, if blood glucose levels fall too low, brain cells will rapidly starve, leading to unconsciousness and death.
Which one of the following most accurately expresses the main conclusion of the argument above?
(A) Each of many different human hormones can by itself raise blood glucose levels.
(B) The reason that many different hormones can each independently raise blood glucose levels is probably a metabolic quirk of the brain.
(C) Although most human cells can produce energy from fats and proteins, brain cells can produce energy only from glucose.
(D) If blood glucose levels fall too low, then brain cells starve, resulting in loss of consciousness and death.
(E) The reason brain cells starve if deprived of glucose is that they can produce energy only from glucose.
Source: LSAT and CR archive
As usual, Kudos will be given for those who answer correctly before the OA is revealed!
Looking at the structure of the passage, the opening statement, the way it is presented, is a fact. The second statement is a possible explanation for the phenomenon,i.e the ability of hormones to raise glucose levels. And, it is supported by another fact - i.e brain cells harness energy only from glucose. The other cells are able to harness energy from fats and proteins - again a fact. The last part, with a conclusion marker 'thus' - gives out an obvious consequence - if deprived of glucose,brain cells starve.
Amongst all answer choices, A,C,D, and E are just plain re-statement of the facts already presented in the argument.
B presents a possible explanation for the ability that many hormones possess - the ability to raise glucose levels individually. Hence B.