#19 - Light is registered in the retina when photons hit

[180bound]

Thanks for clearing that up, it helped a lot!

[guccikittay]

Hi there! I am working through the LR Bible and came across this question.

I have been trying to train myself to read super carefully and not make my own assumptions. So when I read the question and saw that the authors say that "[...] the molecular motion is directly propotional to the temperature of the retina", my thought process went like: "Okay, so temperature affects the molecular motion. Does that mean that cooler temperatures cause this, or warmer temperatures? It doesn't specify, so we don't know."

Then, going into the answers, none of them seemed to fit. I don't fully understand how B can be the answer because how do we know that the opposite (where the animal is in a cooler temperature) wouldn't also have an effect?

Hopefully my question makes sense! Thanks for your time.

[Beatrice Brown]

Hi Gucci! Thanks so much for your question, and welcome to the forum

First, great job on training yourself to read super carefully and not make any of your own assumptions, as these skills are crucial to doing well on the LSAT!

Many students are confused how we can infer that the relationship between amount of molecular motion and temperature of the retina is warmer retina temperature = greater amount of molecular motion rather than cooler retina temperature = greater amount of molecular motion.

The reason we can infer that the relationship is "the higher the temperature of the retina, the greater the amount of molecular motion" is because of the phrase "directly proportional" in the stimulus. A directly proportional relationship means that as one variable increases (in this case, the temperature of the retina), the other variable also increases (in this case, the amount of molecular motion). For the relationship in the stimulus to be "the lower the temperature of the retina, the greater the amount of molecular motion," the stimulus would have needed to use the phrase "inversely proportional." An inversely proportional relationship means that as one variable increases, the other variable decreases.

Let's now look at answer choice (B) to understand why this is a conclusion that is strongly supported by the stimulus. The answer choice tells us when an animal's body temperature matches its surroundings and the animal is in hot surroundings, its visual system is more error-prone than an animal in cold surroundings. From the stimulus, we know that as the temperature of the retina increases, so does the amount of molecular motion. We also know that molecular motion introduces error into visual systems. So if the body temperature (and therefore, temperature of the retina) of an animal is higher, then there is a greater amount of molecular motion. And since molecular motion introduces error, we can infer that a greater amount of molecular motion leads to more error. Combining these facts from the stimulus is consistent with the conclusion stated in answer choice (B), making it the correct answer choice.

To sum up, the key phrase in the stimulus to determine that answer choice (B) is correct is "directly proportional." Because the stimulus uses the phrase "directly proportional," we can determine exactly how retina temperature and the amount of molecular motion are related.

This is definitely a tricky question, but I hope this helps, and please let me know if you have any other questions!

[SGD2021]

Hello, would it be correct to assume that we can make a bit more of a leap in terms of going beyond what is stated in the stimulus to choose answer choice B because the question asks about which CONCLUSION is most strongly supported? In other words, in other most strongly supported questions like this, seeing a question that asks about a conclusion might be an indication that the correct answer choice can extend a bit further in terms of wording (like it being acceptable for "body temperature" to be supported by "retina temperature" in the stimulus)?

[atierney]

Hello,

I would look at Must-Be-True Conclusion questions such as this one as if you were to provide a concise summary of all the information presented. In other words, or the plain words that follow, the idea is to pinpoint the directional arrow, if any, of the information. Each of the pieces of information provided, the premises or statements of fact are like strings on a guitar or harp; they don't exist in isolation, but rather when pulled together (or tied) they generate another idea, another deduction that can be made. I would look at it like that, rather than asking what "jumps" I might be able to make. Like the Most Strongly Supported Questions, these are indeed Must Be True questions; thus, they are questions that are proven correct (via deduction or otherwise) from the information provided in the stimulus.

Let me know if you have further questions on this.

[170LSATsOnly]

After getting this question wrong, I read the explanation and found myself to be quite confused. According to the answer key, option (B) was the correct choice. It explicitly says within the explanation for option (B) that "the last sentence of the stimulus shows that the amount of rhodopsin molecular motion is directly proportional to the temperature of the retina (meaning that when temperatures are lower, molecular motion is lower; when temperatures are higher, molecular motion is higher)..." After re-reading the stimulus, I found nothing that would lead me to choose this option because there is nothing within the stimulus that makes any reference to higher temperatures correlating to higher molecular motion. The test taker doesn't know whether higher molecular motion is a result of higher or lower temperatures.

I would also argue that this information doesn't fall under the "umbrella" of statements in the stimulus because I can think of multiple examples of increased function of the body in colder temperatures than warmer temperatures. I understand that this is a "Most Strongly Supported" question so the answers will have a varying degree of correctness, but I don't understand how the stimulus can backup Option (B) in any way.

[Stephanie Oswalt]

After getting this question wrong, I read the explanation and found myself to be quite confused. According to the answer key, option (B) was the correct choice. It explicitly says within the explanation for option (B) that "the last sentence of the stimulus shows that the amount of rhodopsin molecular motion is directly proportional to the temperature of the retina (meaning that when temperatures are lower, molecular motion is lower; when temperatures are higher, molecular motion is higher)..." After re-reading the stimulus, I found nothing that would lead me to choose this option because there is nothing within the stimulus that makes any reference to higher temperatures correlating to higher molecular motion. The test taker doesn't know whether higher molecular motion is a result of higher or lower temperatures.

I would also argue that this information doesn't fall under the "umbrella" of statements in the stimulus because I can think of multiple examples of increased function of the body in colder temperatures than warmer temperatures. I understand that this is a "Most Strongly Supported" question so the answers will have a varying degree of correctness, but I don't understand how the stimulus can backup Option (B) in any way.

Hi 170LSATsOnly,

Thanks for the post! I moved your post to the thread discussing this question. Please review the discussion starting on page 1 of this thread, and let us know if this helps, or if you still have further questions. In particular, I think this explanation may help address your question.

Thanks!

[Danekim]

Hello,
I am still confused by the this question. The information given states that "the amount of molecular motion is directly proportional to the temperature of the retina." However, it does not specifically state whether an increase or decrease in temperature will cause there to be more molecular motion. It only states it's "directly proportional to it. Couldn't that mean that a decrease in temperature could cause more molecular motion?

Thanks

[Luke Haqq]

Hi Danekim!

You ask,

It only states it's "directly proportional to it. Couldn't that mean that a decrease in temperature could cause more molecular motion?

Think of "directly proportional" as meaning, when one of two variables goes up, so does the other one (and vice versa--when one goes down, so does the other variable). Here, one variable is the amount of molecular motion and the other variable is temperature. The piece of the stimulus that you quoted is saying that the amount of molecular motion increases when the temperature increases.

Answer choice (B) is correct because animals with body temps that match their environment would have warmer retinas in hot environments than they would in cold environments. And increased retina temperature increases the mentioned molecular motion, which in turn introduces errors into the visual system. (B) accurately describes that visual systems of these animals would be more error-prone in hot environments than in cold environments.

[Dancingbambarina]

Dancingbambarina wrote: ↑
Tue Oct 29, 2024 5:06 am
Thanks so much Dave, but honestly this is not covered. I just don’t understand why “normal” is not taken more seriously in the context of the spectrum naturally being normal —> abnormal ? Why is sometimes change shape due to normal molecular motion immediately create a proportional concept instead ?

Thanks very much


Hi, please post questions related to individual LSAT problems in the specific question thread. That keeps all the relevant information together for each problem.

If you restate your entire question there, then we can post a reply. But there are multiple discussions of the proportionality concept, and you'll want to expand on your question about "normal" because it doesn't entirely make sense to me why it's a problem here. Plus, the problem itself introduces the proportionality idea ("The amount of this molecular motion is directly proportional to the temperature of the retina.") so the more info you can provide about what you are asking, the more it will help us if a reply is required.

Thanks!


Hi Dave, Thank you for your help.

Why is "normal" here NOT taken to mean "proper" or "standard". But instead, it is reduced to being a description of variability. I know this may sound strange, but I took this "normal" to not mean normal amount of motion, but instead the kind of motion needed for R molecules to sometimes change shape. In other words, if R molecules were to change shape, it would be if there is "normal" molecular motion, not abnormal, or too fast, or too slow, or too chaotic. "Normal" here is assumed to mean "rate"