Black Americans are, on the whole, about twice as likely as White

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

Why is D wrong,can anyone explain ??

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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

Hey All,

Conclusion: Predisposition to HBP reflects Western high-salt diets and genes adapted to scarcity of salt
Premise: Black Americans twice as likely to get HBP as White Americans. Westernized Black Africans twice as likely to get HBP as White Africans.
Assumption: ???

Strengthen and Weaken questions often relate to assumptions, but more likely when the question asks you to strengthen or weaken the ARGUMENT itself. In this case, we're asked to strengthen the hypothesis (i.e. conclusion), which means we're likely to bring in new information, so it's unlikely we'll be able to predict the assumption...

(A) The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available, are low.
ANSWER: This gives NEW INFORMATION that matches up with the hypothesis (not much salt, no blood pressure problems).

(B) The unusually high salt consumption in certain areas of Africa represents a serious health problem.
PROBLEM: This neither strengthens nor weakens. We want a connection between blood pressure and salt.

(C) Because of their blood pressure levels, most White Africans have markedly decreased their salt consumption.
PROBLEM: This is tricky. Even though it connects blood pressure and salt, it does it in the wrong way. We want to see salt AFFECTING blood pressure. But here we're only told that these people have decreased their salt consumption because of their blood pressure. Has it worked? We don't know.

(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.
PROBLEM: This is less tricky than it looks. This just says a tribe without salt doesn't have high blood pressure. This would strengthen the conclusion that salt causes high blood pressure. But we already know that. We want to know if there's a genetic link that causes those with a history of low-salt diets to develop high blood pressure when moved to the West. This doesn't address the West at all.

(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.
PROBLEM: You could argue this has no effect (what do we care about salt metabolism?) or weakens, because it's breaking the link between history and blood pressure that the conclusion wants to make.

Hope that helps!

-t

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?


(A) The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available, are low.

(B) The unusually high salt consumption in certain areas of Africa represents a serious health problem.

(C) Because of their blood pressure levels, most White Africans have markedly decreased their salt consumption.

(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.

(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.

Hey All,

Conclusion: Predisposition to HBP reflects Western high-salt diets and genes adapted to scarcity of salt
Premise: Black Americans twice as likely to get HBP as White Americans. Westernized Black Africans twice as likely to get HBP as White Africans.
Assumption: ???

Strengthen and Weaken questions often relate to assumptions, but more likely when the question asks you to strengthen or weaken the ARGUMENT itself. In this case, we're asked to strengthen the hypothesis (i.e. conclusion), which means we're likely to bring in new information, so it's unlikely we'll be able to predict the assumption...

(A) The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available, are low.
ANSWER: This gives NEW INFORMATION that matches up with the hypothesis (not much salt, no blood pressure problems).

(B) The unusually high salt consumption in certain areas of Africa represents a serious health problem.
PROBLEM: This neither strengthens nor weakens. We want a connection between blood pressure and salt.

(C) Because of their blood pressure levels, most White Africans have markedly decreased their salt consumption.
PROBLEM: This is tricky. Even though it connects blood pressure and salt, it does it in the wrong way. We want to see salt AFFECTING blood pressure. But here we're only told that these people have decreased their salt consumption because of their blood pressure. Has it worked? We don't know.

(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.
PROBLEM: This is less tricky than it looks. This just says a tribe without salt doesn't have high blood pressure. This would strengthen the conclusion that salt causes high blood pressure. But we already know that. We want to know if there's a genetic link that causes those with a history of low-salt diets to develop high blood pressure when moved to the West. This doesn't address the West at all.

(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.
PROBLEM: You could argue this has no effect (what do we care about salt metabolism?) or weakens, because it's breaking the link between history and blood pressure that the conclusion wants to make.

Hope that helps!

-t

This was so tricky but it made total sense when I saw the right answer.

So, the hypothesis states that the reason BP is high is because of a combo of western high salt diets and genes that had to adapt from a place that typically had a SCARCITY of salt.

A strengthens the hypothesis because it's saying that Senegal and Gambia already had PLENTY of salt so descendents would have low BP because they're genes didn't have to get used to high salt diets.

Posted from my mobile device

This was so tricky but it made total sense when I saw the right answer.

So, the hypothesis states that the reason BP is high is because of a combo of western high salt diets and genes that had to adapt from a place that typically had a SCARCITY of salt.

A strengthens the hypothesis because it's saying that Senegal and Gambia already had PLENTY of salt so descendents would have low BP because they're genes didn't have to get used to high salt diets.

Posted from my mobile device

I still get thrown off. The last bit of the passage says that their genes were adapted to an environmental scarcity, yet A says they descended from those who lived in areas with high salt...

(A) The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available, are low.

(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.

KarishmaB GMATNinja and other experts
AjiteshArun
Can you please help me understand why option E is incorrect?

(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.

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)

Option E(indirect meaning) : Salt metabolism doesn't impact incidence of BP. Nice! The argument is something(interaction of genes and diet) causes higher incidence of BP. Now option E says, something else(salt metabolism) doesn't cause higher incidence of BP. Wouldn't this statement strengthen the argument?