Science Mini-Passage Drill Passage #2

[Legalistic]

Hi,

In the Science Passage #2 about T-cells, I think the entire passage just really went over my head when I was doing it. I'm not restricted by the timing element right now because I'm aiming for accuracy right now. But, I'm worried that I'm not able to grasp a good understanding without the timing element, which makes me question what and how I will perform when timed. After seeing that I got most questions wrong, and also not being able to understand why some correct answers were correct and why some incorrect were incorrect, I decided to write down a short summary of the passage which helped me better understand it. Do you have any other tips for me that will help for now?

For question 2, I chose A as the correct answer. I understand why it's incorrect now. The explanation also says that it's incorrect because the lytic function is inhibited by the tumor itself and not by the specific ability of tumors to escape T-cell surveillance. Could a correct answer say "It's inhibited by the inability of the T-cells to escape the microenvironment of the tumor"? I thought that would make sense because we're told that the defect of the lytic function is exclusive to T-cells residing in the tumor microenvironment only and not anywhere else in the body.

I think question 3 was pretty tough. When I was reading the explanation I found that A is the correct answer. While I found A attractive, I also found E attractive. The explanation for E being incorrect, however, made me question why A was correct. For example E is incorrect because "we need to explain why tumor-infiltrating T-cells exhibit lytic defects, not why T-cells in general do." Makes sense. We need something to weaken that tumor-infiltrating T-cells are inhibited from performing their lytic function because of the tumor itself. But answer choice A never addresses "tumor infiltrating T-cells", is this because it explicitly says that the tumor is caused by a virus that disrupts the normal functioning of T-cells. In this, they're making direct reference to the tumor, which means they'd be referring to tumor infiltrating T-cells right?

Is there something else I was supposed to understand from A?

Kindly guide me on how I should've approached the question, if mine was incorrect.

Thank you in advance! (very much)

[Adam Tyson]

This passage was a real bear, wasn't it, Legalistic? It made my head spin. The key is to focus less on the details and more on the structure. The first paragraph is introducing a recently confirmed but longstanding theory that cancer causes a type of immune cell response in humans, and it tells us a little bit about research and implications. It's dense, but if we keep ourselves from getting lost in the weeds then that's all it is.

The second paragraph describes a problem, a paradox, and explores some hypotheses that attempt to resolve that paradox. Again, very dense and filled with scientific jargon, but stick to the big picture and you won't get lost.

The problem here is in the questions, which are very focused on the science and the details. This means you should expect to do a lot of re-reading to find those details and scrutinize them, unlike on the initial read through. Broad focus on the first pass through the passage, and then a narrow, laser-like focus on finding and re-reading the information that answers the questions.

I'm not sure your proposed answer to question 2 would be any better, because there is nothing in the passage about the T-cells being unable to escape. It's just that while they are inside the tumors, they don't work, and the author thinks the tumor is preventing them from working. That's why E is correct there - the function is affected by where the cells are, either inside the tumor or outside of it.

For question 3, the problem with answer E is that it tells us nothing about whether or not tumors are the cause of the problem in those T-cells. All it tells us is that pathogens can cause those problems. But are those pathogens related to the tumors somehow? If they are, then E might even strengthen that hypothesis. That's in addition to the explanation in the workbook, of course. We need to focus on the T-cells in the tumors, not on T-cells generally. For that question, the focus was supposed to be entirely on the causal claim, and it should be attacked with standard causal strategies - alternate cause, cause without effect, effect without cause, reversed cause and effect, or a problem with the data.

[sdb606]

I still don't see why A is correct. I eliminated A because I thought it was an OPPOSITE answer. The hypothesis is that lytic function is location dependent. Yes in tumor, no out of tumor. Answer A simply explains why lytic function fails in tumors, which supports the hypothesis by providing an explanation for why T cells inside tumors would fail: because there are viruses around which interfere with lysis.

I think C should be right because C, accepted as true, proves the hypothesis of the "some scientists" in line 23 who are the opponents of Dr. Genart, therefore destroying the hypothesis. Imagine if I hypothesized that Martian men are green because of evidence suggesting that all living beings on Mars would have a molecule that makes them green. Now suppose someone else conclusively proves there is no life on Mars. That would certainly challenge my hypothesis. By this analogy, C should be correct.

I don't understand the book's explanation for A. The book says the hypothesis to be weakened is that, " the lytic function of tumor-infiltrating T-cells is inhibited by the tumor itself." But this fails the Fact Test because no where in the passage does it say the tumor itself causes lytic defects. The passages hypothesizes that the lytic defect is acquired in the tumor, not that the tumor causes the lytic defect. Answer A provides a good explanation for how a lytic defect could be acquired in a tumor and so should therefore be incorrect.

[Jeremy Press]

Hi sdb,

Check out where the author ultimately takes the argument that they began in lines 28-30. At the end of the passage, the author asserts that when the T-cells in the tumor are "purified" (removed from the tumor and its influence), their lytic function is restored. Now, this by itself could be consistent with a virus inside the tumor causing the lytic defect. But the last line of the passage indicates that the author actually has a more specific hypothesis in mind here. "These observations support the hypothesis that the lytic function of tumor-infiltrating T-cells is inhibited by the tumor itself." The line 28-30 hypothesis, and particularly the author's read of it as clarified at the end of the paragraph, is that the tumor itself is the cause of the defect. Answer choice A simply postulates a potential alternate cause of the lytic defect: rather than the tumor itself inhibiting T-cell function, it's the virus disrupting that function.

The context makes clear, then, that it's more than just location the author is arguing about. The author argues that the location element makes it clear that the tumor itself is doing the work. Answer choice A suggests otherwise.

Answer choice C is incorrect because it's not speaking specifically to a defect in the lytic function of T-cells that actually make it into a tumor. Rather, it's talking about a different situation where some tumors don't even get detected by T-cells. That wouldn't shed any light on those "purified" T-cells (the ones we know about that actually did lose their lytic function, then got it back) in lines 33-35. So the evidence in answer choice C does suggest there are other ways tumors avoid being destroyed by T-cells. But that doesn't do anything to shed light on the tumors we know about that actually do have T-cells in them but where the T-cells nevertheless still don't work.

I hope this helps!