#16 - Scientists have recently discovered that, in doses massive enough to kill cells, almost any

[Administrator]

Complete Question Explanation

Must Be True, CE. The correct answer choice is (B).

Answer choice (A):

Answer choice (B): This is the correct answer choice.

Answer choice (C):

Answer choice (D):

Answer choice (E):

This explanation is still in progress. Please post any questions below!

[saiffshaikhh@gmail.com]

Complete Question Explanation

Must Be True, CE. The correct answer choice is (B).

Answer choice (A):

Answer choice (B): This is the correct answer choice.

Answer choice (C):

Answer choice (D):

Answer choice (E):

This explanation is still in progress. Please post any questions below!

Can you explain how D is incorrect and B is the appropriate choice?

[Amber Thomas]

Hi saiffshaikhh!

Let's start by breaking down our stimulus:

Premise 1: We have recently discovered that, in doses large enough to kill cells, almost any chemical is carcinogenic. This is because cell death causes rapid cell division, which promotes cancer-causing mutations.
Premise 2: Some chemicals are also carcinogenic without causing cell death.
Premise 3: Until recently, studies of the carcinogenicity of food additives have involved administering large doses to test animals. These doses are larger than the largest possible level of exposure to humans, and massive enough to kill large numbers of cells in the animals. The relevant cancer rates of these animals would then be observed.

Let's pre-phrase our answer. We know that a) any chemical in a large enough dose is carcinogenic, and b) most animal testing of food additives has been done with extremely large doses that cause cell death in the test animals. From this, we can deduce that perhaps the carcinogenicity of food additives has been overstated.

Now, let's look at our answer choices.

Answer Choice B states: Until now results of carcinogenicity studies encouraged overestimation of the degree to which some food additives are carcinogenic.

This follows from our stimulus! Again, we know that any chemical in a large enough dose is carcinogenic. Test animals in carcinogenicity studies are always given larger doses than humans could ever be exposed to, and these doses are enough to cause cell death. So, in animal testing, we are seeing the carcinogenicity results from cell death, as opposed to the chemical itself. Therefore, the chemical itself may not actually be inherently carcinogenic.

Answer Choice D states: Carcinogenic chemicals are usually absorbed in small doses in the natural environment.

This is out of scope. The stimulus doesn't actually give us all that much information about carcinogenic chemicals. Further, the only context we have for carcinogenic chemicals is within testing for food additives. So, we have no reason to make any assumptions/inferences about carcinogenic chemicals in the natural environment.

I hope this helps!