Advertisement for a lactase supplement: Lactase, an enzyme produced by the body, aids in the digestion of lactose, a natural sugar found in dairy foods. Many subjects in an experiment who drank a liter of milk on an empty stomach showed signs of lactose intolerance—difficulty in digesting dairy products because of insufficient lactase. Thus, extrapolating from the number of subjects adversely affected, at least 50 million people in North America alone should take lactase supplements.Conclusion:
at least 50 million people in North America alone should take lactase supplements Support:
Many subjects in an experiment who drank a liter of milk on an empty stomach showed signs of lactose intolerance—difficulty in digesting dairy products because of insufficient lactase. and
extrapolating from the number of subjects adversely affected We see that the reasoning of the argument is basically the following: since a certain proportion of people in a group who drank a liter of milk showed signs of lactose intolerance—difficulty in digesting dairy products because of insufficient lactase—it can be determined that 50 million people in North America should take lactase supplements.
Which one of the following statements, if true, most seriously weakens the argument?The correct answer to this Weaken question will somehow indicate that, even though many people in the group showed signs of difficulty in digesting dairy products because of insufficient lactase, the conclusion may not be true.
Also, key to identifying the correct answer will be careful reading because it would be easy to get confused as a result of the similarity between the word "lactase," which names an enzyme, and "lactose," which names a sugar found in dairy foods.
(A) Eating solid food when drinking milk can decrease the amount of lactase produced by the body.If anything, this choice strengthens, rather than weakens, the argument.
After all, in the experiment, people showed signs of lactose intolerance when they drank milk "on an empty stomach," meaning without eating anything else.
So, given what this choice says, if people consume solid food along with dairy products, even more of them will show signs of lactose intolerance. After all, given what this choice says, people would have even less lactase for digesting dairy products any time they consume solid food along with dairy products.
Eliminate.
(B) Most people who consume dairy products consume less lactose at each meal than the amount found in a liter of milk.This choice is interesting.
The conclusion is based on the fact that people who drank a liter of milk showed signs of "lactose intolerance—difficulty in digesting dairy products because of insufficient lactase."
So, if most people don't normally consume at a meal as much lactose as is found in a liter of milk, then the conclusion may not be correct.
After all, if most people consume less lactose, then they don't need as much lactase. So, in that case, they may not have difficulty digesting dairy products because of insufficient lactase because they may have sufficient lactase for digesting less lactose.
Accordingly, the proportion of participants who showed signs of lactose intolerance in the experiment may not be indicative of the proportion of people in North America who could benefit from taking lactase supplements.
Keep.
(C) The production of lactase by the human body increases with age.This choice is tempting because it's possible that people in general are older than the participants in the experiment, in which case people in the population at large could produce more lactase than the participants did.
However, the experimental results don't specify any particular ages. So, this choice isn't clearly related to the results.
Also, presumably, the "extrapolating" mentioned in the argument could take age into account.
Often, LSAT Weaken questions have a second answer choice like this one that almost or arguably works, but since choice (B) clearly works, we can eliminate this one and choose (B).
Eliminate.
(D) Lactose intolerance can interfere with proper nutrition.This choice strengthens, rather than weakens, the argument by providing an additional reason to take lactase supplements.
Eliminate.
(E) Some dairy foods, such as cheese, contain a form of lactose more difficult to digest than that found in milk.If anything, this choice strengthens, rather than weakens, the argument by indicating that people may need lactase supplements even more than results of the experiment indicate.
Eliminate.
Correct answer: B