Skywalker18 wrote:
Black Americans are, on the whole, about twice as likely as White Americans to develop high blood pressure. This likelihood also holds for westernized Black Africans when compared to White Africans. Researchers have hypothesized that this predisposition in westernized Blacks may reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt.
Which of the following statements about present-day, westernized Black Africans, if true, would most tend to confirm the researchers’ hypothesis?
Boil it down - This predisposition in westernized Blacks may reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt.
environmental scarcity of salt---> genes in BAs have adapted to low or NO salt diets
So western high-salt diets in BAs --> high BP
(A) The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available, are low. - Correct - So in these people the cause(environmental scarcity of salt) wasn't applicable. Thus the effect is also not present.
(B) The unusually high salt consumption in certain areas of Africa represents a serious health problem. - Irrelevant
(C) Because of their blood pressure levels, most White Africans have markedly decreased their salt consumption. - Irrelevant
(D) Blood pressures are low among the Yoruba, who, throughout their history, have been situated far inland from sources of sea salt and far south of Saharan salt mines. - Irrelevant - Firstly we need to assume that Yoruba is an African tribe and this seems to be an exception to the norm mentioned
(E) No significant differences in salt metabolism have been found between those people who have had salt available throughout their history and those who have not. - Weakens - this goes against the researches hypothesis
In OA-A (also in option D),
we need to know(assume) that Senegal and Gambia are part of Africa and Blacks lived in those countries. Also, although option D is incorrect, the question expects us to assume that Yoruba is an African tribe?
I knew that Senegal is an African country but hadn't heard about Gambia. So, can the GMAT expect us to assume(know) such things?
Answer A
AjiteshArun ,
GMATNinja ,
MagooshExpert ,
GMATGuruNY ,
VeritasKarishma ,
VeritasPrepBrian ,
MartyMurray , other experts - please enlighten
Black Americans and westernised Black Africans are twice as likely to develop high BP as compared with Whites.
Hypothesis: Higher incidence of high BP may reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt. (Blacks faced scarcity of salt so genes adapted to it but now the westernised diet has abundance of salt which is causing high BP)
Which of the following statements about present-day, westernized Black Africans, if true, would most tend to confirm the researchers’ hypothesis?
The given statements are about "westernised Black Africans". Which will strengthen the hypothesis?
(A) The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available, are low.
For people who were situated in areas where salt was available, BP is low - perhaps because their genes did not need to adapt to low salt and hence high salt does not bother them now. So this gives more credibility to the hypothesis that high BP reflects an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt.
(B) The unusually high salt consumption in certain areas of Africa represents a serious health problem.
"Unusually high salt consumption" has no connection to our hypothesis.
(C) Because of their blood pressure levels, most White Africans have markedly decreased their salt consumption.
Our discussion is black Africans vs white Africans. The BP levels of white Africans is irrelevant.
(D) Blood pressures are low among the Yoruba, who, throughout their history, have been situated far inland from sources of sea salt and far south of Saharan salt mines.
This does not support our hypothesis. It goes against what our hypothesis would predict.
(E) No significant differences in salt metabolism have been found between those people who have had salt available throughout their history and those who have not.
We don't know how salt metabolism impacts our hypothesis. Irrelevant.
Answer (A)
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