Scientists have long thought that omega-3 fatty acids

Question

Scientists have long thought that omega-3 fatty acids in fish oil tend to lower blood cholesterol and strongly suspected that a diet that includes a modest amount of fish would provide substantial health benefits. Now these views have acquired strong support from a recent study showing that middle-aged people who eat fish twice a week are nearly 30 percent less likely to develop heart disease than are those who do not eat fish.

Which one of the following is an assumption required by the argument?

(A) The test subjects in the recent study who did not eat fish were not vegetarians.

(B) The test subjects in the recent study who ate fish twice a week did not have a diet that was otherwise conducive to the development of heart disease.

(C) The test subjects in the recent study who did not eat fish were significantly more likely to eat red meat several times per week than were those who did eat fish.

(D) The test subjects in the recent study who ate fish twice a week were not significantly more likely than those who did not to engage regularly in activities known to augment cardio-respiratory health.

(E) The test subjects in the recent study who ate fish twice a week were no more likely than those who did not to have sedentary
occupations.

Source: LSAT

dexter100 · Answer

the answer is B

the argument is assuming that the people who ate fish were not consuming anything that would lead to heart problems.

like my answer? HIT KUDOS!

arvind910619 · Answer

Imo D 
If people did activities that improve heart and respiratory then the conclusion that eating fish twice a week reduces heart diseases will fail.

chesstitans · Answer

this is what I feel distressed about gmat questions. This question is not really about assumption, but a strengthen question, because it eliminates one other possibility.

Nevertheless, since other options are wrong, D is correct.

A_Nishith · Answer

The argument claims that a recent study shows that middle-aged people who eat fish twice a week are nearly 30 percent less likely to develop heart disease compared to those who do not eat fish. This supports the idea that omega-3 fatty acids from fish have health benefits.

For this argument to hold, the author must assume that eating fish is the key factor that leads to a lower risk of heart disease, and not some other lifestyle factors that might be different between the two groups (those who eat fish and those who don’t). Let's evaluate each answer choice to identify the assumption required for the argument to be valid.

(A) The test subjects in the recent study who did not eat fish were not vegetarians.

Whether the non-fish eaters were vegetarians doesn't necessarily affect the argument, because the comparison is between fish eaters and non-fish eaters. The study is about the effect of fish consumption, so this assumption is not required. Vegetarians could have various other health habits, but it’s not central to the claim being made.

(B) The test subjects in the recent study who ate fish twice a week did not have a diet that was otherwise conducive to the development of heart disease.

This is a strong contender.  If the fish-eating group also had an otherwise unhealthy diet that contributed to heart disease, it could undermine the argument that fish consumption is what lowered their risk of heart disease. The author assumes that fish eaters do not have other negative dietary habits that would cause heart disease, so that the reduction in risk can be attributed to eating fish. This assumption is necessary for the conclusion to hold.

(C) The test subjects in the recent study who did not eat fish were significantly more likely to eat red meat several times per week than were those who did eat fish.

This assumption introduces a possible comparison to red meat consumption. However, it is not required by the argument. The claim is about the health benefits of eating fish, not about differences in red meat consumption between the groups. So, this is not necessary for the argument.

(D) The test subjects in the recent study who ate fish twice a week were not significantly more likely than those who did not to engage regularly in activities known to augment cardio-respiratory health.

This is a good option as well.  If fish eaters were significantly more likely to engage in activities (like exercise) that improve heart health, then the lower risk of heart disease could be due to those activities rather than fish consumption. The argument assumes that the fish-eating group did not have other habits, like more exercise, that would account for their better heart health. This is also an important assumption.

(E) The test subjects in the recent study who ate fish twice a week were no more likely than those who did not to have sedentary occupations.

While this could affect health, the focus is on the broader lifestyle differences between fish eaters and non-fish eaters. Whether they had sedentary jobs doesn’t seem crucial to the argument, which is about the overall effects of fish consumption. This is not a required assumption.

Conclusion: 
The best answers are (B) and (D), as  both ensure that other factors (like unhealthy diets or greater physical activity) aren’t responsible for the observed difference in heart disease risk. Since we need one assumption, (B) is slightly stronger because it directly addresses the impact of diet, which is central to the argument about omega-3 fatty acids.  Therefore, the  best answer is (B).

Scientists have long thought that omega-3 fatty acids

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Scientists have long thought that omega-3 fatty acids

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

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