A certain tropical island received food donations in the form of

I pick A.

The way I read it, the stem says that the rats developed liver cancer when fed casein, which is a milk protein. However, the stem argues that this happened because the rats were already exposed to aflatoxin.

Thus the argument is that for rats who are exposed to aflatoxin and then fed casein, liver cancer develops.

Similary, if the humans in the tropics are already exposed to aflatoxin, and then consume the powdered milk which contains casein, liver cancer develops as well

Hi Sachin,

Let me see if I can help. Simply the passage is saying:

Milk was imported to the island

People on the island got liver cancer.

This is blamed on the imported milk.

Because research has shown that if people have milk protein and aflatoxin.

SO

We know they have milk, we know they have cancer, we need an answer that also tells us they have aflatoxin. Answer A does that.

E tells us nothing about the existence of aflatoxin without which, the conclusion is not valid

Hope that helps.

James

Im not sure. i don't know why A. Doesn't A say that milk wasn't the cause???

from A we do not know that the aflatoxins in peanuts have anything to do with the liver cancers. all A tells us is aflatoxin from the peanuts is already present in the diets of these residents. the rat relationship is to say that the aflatoxin in milk protein causes cancer. kinda inverted logic.

x = aflatoxins in milk protein
y = aflatoxins in peanuts

not y then x

OA=A

The argument asks how the experiment related to what cause the cancer in the island. In an ordinary CR question, I would try to find the relationship between the experiment and the milk. However, this isn't the case. Since milk cause cancer on the island, the experiment is relevant because it might be that Peanuts is the cause of the cancer on the island.

Great explanation BKK, i would like to add just what's stated in the passage, that after the donation of the milk, the islanders sow a sharp increase in liver cancer. Becasue of that they explaioned the experiment with milk, and because the nuts have the same ingredient as milk, it made the cases of liver cancer rise.

why is the answer not E folks?
kindly help..
_________________

Hi James,
I believe we are trying to weaken the claim that aflatoxin caused cancer.

how does A weaken?
_________________

Hi Sachin,

that's not as I see it.

We are asked to logically conclude the passage

The passage's conclusion is that the introduction of milk caused the increase in cancer.

We need to find out the reason why they think this.

The combination of the info in the question and the info given in A does that:

Question: aflatoxin + milk protein causes cancer. Milk (and hence milk protein) was given to the islanders.

All we are missing is the presence of aflatoxin...

Option A: Islanders have aflatoxin through eating peanuts

I thought option B as correct. But it was wrong.
It says:
the liver is more sensitive to carcinogens, of which aflatoxin may be one, than most other bodily organs

When liver is more sensitive, it will get the the fault easier.
This option might be wrong because it says of which aflatoxin may be one!! Means aflatoxin might or might not b the one to which the liver is more sensitive.
Please correct me if I am wrong.

Which of the following most logically completes the passage?

P1: A certain tropical island received food donations in the form of powdered milk for distribution to its poorest residents, who were thought to be malnourished. [milk distributed to malnutrition people]
Subsequently, the rate of liver cancers among those islanders increased sharply. [Post that liver cancer increases]

The donated milk was probably to blame: recent laboratory research on rats has shown that rats briefly exposed to the substances aflatoxin tend to develop liver cancer when fed casein, a milk protein.
[Aflatoxin + casein -> LC ]
This result is relevant because _______.

>>Just think abt this argument as a normal day conversation with ur friend. We need a answer which can take this discussion forward...

A. in the tropics, peanuts, a staple of these island residents, support a mold growth that produces aflatoxin
>> Correct.
B. the liver is more sensitive to carcinogens, of which aflatoxin may be one, than most other bodily organs
>> Comparison with other organ doesnt matter. V need to link with AF with MP.
C. casein is not the only protein contained in milk
>> V dont care abt other protein.
D. powdered milk is the most appropriate form in which to send milk to a tropical destination
>> Irrelevant.
E. the people who were given the donated milk had been screened for their ability to digest milk
>> Irrelevant

Conclusion is that milk is probably causing liver cancer. One evidence is given that rats fed with milk protein when exposed to aflatoxin developed liver cancer.

In order to complete the argument we need to show that island residents were exposed to aflatoxin while consuming milk.

A. in the tropics, peanuts, a staple of these island residents, support a mold growth that produces aflatoxin. This is what we were looking for
B. the liver is more sensitive to carcinogens, of which aflatoxin may be one, than most other bodily organs It does'nt support how residents are exposed to aflatoxin
C. casein is not the only protein contained in milk Not talking about aflatoxin
D. powdered milk is the most appropriate form in which to send milk to a tropical destination. good for residents, not for us
E. the people who were given the donated milk had been screened for their ability to digest milk. screening does tell us anything about aflatoxin
_________________

Lets summarize the argument:-
Powdered milk given to tropical islanders -> rate of Liver cancer increased.
Conclusion :- Milk powder caused cancer because same effect was seen in case of rats who were fed CASEIN (milk protein found in milk obviously) and exposed to AFLATOXIN.
So, in case of rats : AFLATOXIN + CASEIN (found in milk) -> cancer;
Now if the cancer incidence in islanders is attributed to milk powder intake by considering analogy of the incidence in rats, then obviously other component (in the highlighted part) AFLATOXIN must also be involved.
Option A exactly tells us this – “peanuts, a staple of these island residents, support a mold growth that produces aflatoxin”.
This means that islanders consumed AFLATOXIN as well as CASEIN (exactly like rats) that lead to cancer.

The answer is A
We have to connect two ideas expressed in the argument .

A certain tropical island received food donations in the form of powdered milk for distribution to its poorest residents, who were thought to be malnourished. Subsequently, the rate of liver cancers among those islanders increased sharply

The donated milk was probably to blame: recent laboratory research on rats has shown that rats briefly exposed to the substances aflatoxin tend to develop liver cancer when fed casein, a milk protein.

No we can see that people were subjected to aflatoxin because of their staple diet peanuts , thus they are likely to get liver cancer as per the result .
Hope it helps

I am not able to understand why A is correct and B is wrong.

As per A, islanders are already exposed to Aflatoxin. So how Milk can be blamed ?

Read the sentence carefully: "rats has shown that rats briefly exposed to the substance aflatoxin tend to develop liver cancer when fed casein, a milk protein."
So as previous people said, AFLATOXIN + CASEIN (from milk) = cancer.
The passage doesnt say either substance alone is gonna cause cancer, it only says when both combine together = cancer.

So we have milk CASEIN from donation, we need to find the AFLATOXIN, which is A, ALATOXIN is found in tropics peanuts mold.
Choice B is not related to the "recent lab research"

I can see all flavors of explanations are provided so nothing much to add but will try a bit. I did falter at first and after re reading the sentence I understand why answer A is correct. One has to focus on sentence "recent laboratory research on rats has shown that rats briefly exposed to the substance aflatoxin tend to develop liver cancer when fed casein, a milk protein." . Later part says 'aflatoxin ' fed casein from milk and I missed / over read this part. I was assuming aflatoxin is coming from casein /milk and so was not able to link back.

But now all clear , Cancer is caused by aflatoxin and casein and same 2 entities we have to find in human body. And only option A gives that answer.

Thanks to our folks, I think we already had a clear explanation for the correct answer.
I just wanna give it a try, and here what my thinking about this stem:

The argument's information:
- The powdered MILK was DONATED to an island RESIDENTS.
- Since then, the incidence of LIVER CANCER AMONG THESE RESIDENTS has INCREASED.
- A research has shown that RATS suffer from THE SAME LIVER CANCER when they EXPOSED TO AFLATOXIN and FED CASEIN (IN MILK)
- The research result has proved that DONATED MILK is responsible for the LIVER CANCER incidence among island RESIDENTS because _____

We need to strengthen this argument, finding something missing in the case of the RESIDENTS... They consumed milk, which means they took-in CASEIN, so we need to find which source provides them with AFLATOXIN.

(A) Yes. They absorbed AFLATOXIN from peanuts. We have enough hints to make up LIVER CANCER for RESIDENTS.
(B) This choice provides very slight hint that AFLATOXIN MAY be one of the factors making up LIVER CANCER, but we do not know whether the RESIDENTS exposed to AFLATOXIN or not. -> out of scope.
(C) The other kinds of protein do not matter here, we only need CASEIN in milk + AFLATOXIN somewhere else -> out of scope
(D) Nothing to do with the types of milk. As long as it is milk, it contains CASEIN -> out of scope
(E) This screening procedure aimed to prove whether the RESIDENTS can fully absorb the milk's nutrition including CASEIN. Still nothing about AFLATOXIN.

Let me explain,
1. milk is imported to an island - people got cancer.

Scientists have decided to find the reason. They did experiment on Lab rats.

2. laboratory rats already exposed to aflatoxin developed cancer when they fed milk.
what might be reason ? ("because" in the question seeks a reason.)

well, people in the island already consume peanut, which has aflatoxin. ( similar to the situation in which lab rats already exposed to aflatoxin developed cancer.) What did we understand from this ?

Exposing to aflatoxin before consuming milk is the reason for cancer!

So, option A.