Feeder —> /Birds

Feeder —> /Cover

______

/Cover —> /Birds

Kind of like...

A -> B

A -> C

______

C -> B

If a tire's pressure is too low (A), the tire will wear out prematurely (B). But tire pressure will become too low (A) only if the car owner neglects to check the pressure regularly (C). So a tire will wear out prematurely (B) if the car owner neglects to check the pressure regularly (C).

If a tire's pressure is too low (A) --> the tire will wear out prematurely (B)

Tire pressure will become too low (A) --> the car owner neglects to check the pressure regularly (C) [remember the only if = necessary]

____

If the car owner neglects to check the pressure regularly (C) --> a tire will wear out prematurely (B)

Stimulus: Lower than B minus —> missed at least one session

Contrapositive: /Missed at least one session --> /Lower than B-minus

/Missed at least one session = Perfect attendance

/Lower than B-minus = B-minus or higher

Meaning: Perfect attendance —> B minus or higher

Stimulus: Most students who took Spanish 101 last semester attended every session.

Attended every session = Perfect attendance

Most students = attended every class = Perfect attendance —> B minus or higher [which is what AC (E) says]

My thoughts exactly. If RDCs dig chambers that remain filled with water even when the surrounding wetlands dry up, and larvae of dragonflies can survive only in water, how are they (the larvae at least) more likely to survive in areas with more RDCs? Wouldn't they face MORE danger there, since that would be the only environment with water where they can survive (per the stimulus), where they would be surrounded by RDCs that they are subject of predation to? At least for B, you can say well adult dragonflies protect their larvae, and since the adults aren't threatened by RDCs, then dragonflies can remain healthy (even if they're an endangered species) with the RDC than without.

And the thing too: "well you can't assume that adult dragonflies would protect their larvae" (for AC (B)) - well how can the dragonflies be more healthy with more RDCs (per AC (A)) if they find themselves in an environment with more RDCs (like the chambers)? --> RDC prey on larvae - OK. Let's put dragonflies (larvae and otherwise) in a chamber that remains filled with water even when the surrounding wetlands dry up, and they can only survive there - what's their surviving mechanism (at least for the larvae) if not the protection of adults?

I picked AC (B). The logic behind my picking it was as follows:

Although it says that the dragonflies are endangered, it says that the larvae (i.e. juvenile, young dragonflies) survive only in water where they are subject to predation from the RDC. So if the young dragonflies are subject to predation, why would the fact that RDCs do no threaten adult dragonflies (presumably who defend their larvae) not explain that dragonfly populations are more likely to remain healthy in areas where red devil crayfish are present than in areas without red devil crayfish?

Adult dragonflies, which are not threatened by RDCs, protect juvenile dragonflies (which are threatened by RDCs). Hence why their (dragonflies') survival (given the context of the stimulus, we're not talking about their other sources of danger) is more likely if adults (not threatened) are protecting the young ones.

For AC (A) - if RDCs dig chambers that remain filled with water even when the surrounding wetlands dry up, and larvae of dragonflies can survive only in water, how are they more likely to survive in areas with RDCs? Wouldn't they face MORE danger there, since that would be the only environment with water where they can survive where they would be surrounded by RDCs that they are subject of predation to?

So is the term referenced in the question "compromise" or "compromises"? Because the singular one is used in a different meaning than the plural one (for the correct answer); the difference with "betray" is that there is "betrays" and "betraying", which we then can associate with AC A.

Based on the stimulus, on what basis can we assume that a higher body temperature is the equivalent of a higher retina temperature (which is what is implied in this question)? I understand how B is correct if you do make that assumption, but how can we know when we can make that leap (high body temp = higher retina temp) or not (because nothing here seems to suggest that this is the case)?

Long-winded description here, but hopefully it will help you:

• FS = Fuzzy seeds

• LS = Long stems

• WF = White flowers

• TS = Thorny seapods

• CL = Curled leaves

• X = Plant X

What we know from the premises:

1. FS —> LS and /WF } Contrapositive = WF or /LS —> /FS

2. CL —> WF

3. TS —> CL

4. X —> LS and CL

Looking at what we have, #4 Can be branched into two:

a) X —> LS } Based on this, can we conclude anything from the premises? Not really - we don't have anything that LS on its own leads to. Sure, we have FS leading to LS (but not only FS, also /WF), and we have no evidence to believe that X is either FS or also leads to /WF.

b) X —> CL } from #2, we know that CL --> WF (so we can say X --> CL --> WF).

We also know, from the contrapositive in #1, that if you have WF, you can have /FS. Mind you, you can have WF or /LS, you don't need to have both.

Combining these two ideas, you have the following:

>>> X —> CL —> WF —> /FS

!!! Important to note: having LS does not break this chain! As I mentioned in (a), having LS doesn't prevent you from having anything (you can say that the contrapositive from #4, if you don't have LS you don't have plant X, but that's irrelevant to our example here). Also, for the contrapositive of #1: you know you have WF, and it's either WF or /LS that leads you to /FS. You satisfy that condition - you know you have WF, guaranteeing /FS (whether you have LS or not - in this case, you do!)

Now, let's see:

• Plant X: has Curled leaves.

• Plant X: having curled leaves --> has White flowers.

• Plant X: having CL and WF --> does not have Fuzzy seeds.

Looking at answer choice C, that's exactly what is states: Plant X has White flowers but not fuzzy seeds, which is exactly in line with X —> CL —> WF —> /FS.

The way I understood it:

• P1. FQ and /W

• P2. MP

_____

• Conclusion: Hire Delacruz

What we know: Don't hire Krall, because Delacruz is a candidate and fully qualified.

So, Delacruz = FQ. OK.

AC [E]: "None of the candidates already works for Arvue, and Delacruz is the candidate who would be most productive in the new position."

a) What we know from this: all candidates are /W (both Krall and Delacruz as well).

• For P1: Delacruz = /W, Krall = /W; so for P1, we know Delacruz is both FQ (from stimulus) and /W (from the AC)

b) Delacruz = MP (so for P2: we know that Delacruz fits this as well; it does not tell us anything about Krall, but if Delacruz is MP, it's safe to assume Krall is not)

So, what do we have here for each:

Krall = /W.

Delacruz = FQ and /W, and also MP.

Well, looking at

• P1. FQ and /W

• P2. MP

_____

• Conclusion: Hire Delacruz

Seems like this fits with the trigger for the rule.

Conclusion: The general principle—if one ought to do something then one can do it—does not always hold true.

• Should --> Can = Not always true

--> In other words: the idea that "because you should do something, you can do it", is NOT always true.

Evidence: You make a promise, you run into a traffic jam, you can't keep it.

• Promise --> (unforeseen jam) --> /Can

Let's write it out.

1. Just because you should do something, it does not mean you can do it. } OK.

2. You make a promise to someone. } The (albeit unstated) idea is that you SHOULD keep your promise (from the general idea that promises should be kept).

3. Combine #1 and #2 --> Just because you should keep your promise, it does not mean you can keep it.

4. Something happens to you (like a traffic jam), and you cannot keep it. } We know from above that you made a promise, and that you can't keep it.

   But... just because you can't keep a promise (for whatever reason), does it mean that you SHOULD not keep it? In other words, the fact that you can't keep your promise relieve you from the obligation to keep your promise?

   Clearly not; you SHOULD still keep (or try to) your promise, even if you can't actually do it.

5. It's important to differentiate between what you should/shouldn't do versus what you can/can't do. You can have situations when you should and can, or should and can't [the latter being our conclusion, essentially, as it states the former is not always true]

1. The diet of Heliothis subflexa caterpillars consists entirely of fruit from plants of the genus Physalis.

2. These fruit do not contain linolenic acid, which is necessary to the growth and maturation of many insects other than H. subflexa.

3. Linolenic acid in an insect's diet is also necessary for the production of a chemical called volicitin.

• V -> L

1. While most caterpillar species have volicitin in their saliva, H. subflexa does not.

• HS -> /V

• C -m-> V

_____

You have: most Cs are Vs, and all Vs are Ls. Therefore: if most caterpillars have volicitin, and all who have volicitin guarantee linolenic acid (i.e. volicitin leads to linolenic acid, in other words = is a source of acid), then most caterpillars have sources of linolenic acid in their diets.

Is the idea/trick for C also that, it states "... patients who change their relationships with other people will thereby find relief from at least some of their troubles." --> we can't conclude whether it's positive change (like it says in the stimulus)? What if it's referring to negative change (i.e. deterioration of relationships)? Does this mean that the deterioration of relationships (i.e. change in relationships) will allow people to find relief from some of their troubles?

A = Freelance journalists

B = Sell their work to magazines that have lax editorial standards

C = Self-respecting writer

This gives us the following:

• Some A are B.

• No C is B.

  _____

  Some C are not A.

Look at [C], which is identical in terms of structure:

A = Students

B = Prefer history to mathematics

C = Member of the Calculus Club

• Some A are B.

• No C is B.

  _____

  Some C are not A.

AC [E]: The conditions at a pond are beneficial to turtles only if the water in the pond is not acidic.

P1. Thriving —> Beneficial

P2. Acidic

_____

/Thriving population of turtles

[E] Assumption: Beneficial —> /Acidic } Contrapositive = Acidic --> /Beneficial

Contrapositive of P1: /Beneficial --> Thriving

So we know you have Acidic (from P2), which leads you to /Beneficial (from contrapositive of the assumption), which then leads you to /Thriving (contrapositive of P1), which is your conclusion.

P1. Thriving —> Beneficial [or, /Beneficial --> /Thriving]

P2. Acidic (this is a premise on it's own, we can't use the contrapositive, so we have to take it as is and see if any of the other premises allow us to draw the conclusion with this one being as is)

Assumption: Beneficial —> /Acidic [or, Acidic --> /Beneficial]

_____

/Thriving population of turtles

I would just like to clarify AC (C). Looking at the premises:

1. Valuable —> Well-run

2. Large and well-run -s-> FT

3. Small and well-run -s-> PT

4. Large and Valuable [and well Run] -s-> Open all year

5. Small -m-> /Open all year

"Some zoos that make valuable contributions to their communities have only part-time veterinarians on staff."

We know that if a zoo makes valuable contributions, it is well-run (P1). So if we know that the zoo makes valuable contributions, why is it wrong to assume that it is well-run? How is this reversing P1 (i.e. Well-run -> Valuable)? Because then, if it makes valuable contributions (which, being a sufficient condition, guarantees that it is well-run), you can say that it's a small zoo that is well-run and only has PT (i.e. PT) on staff. Why do you strictly have to go off of P3?

P1: Valuable --> Well-run

P3: Small and well-run -s-> PT

AC [C]: Make valuable contributions only have PT } If you make valuable contributions, you are well-run (from P1). And then you can use P3 [Small + well-run -s-> PT].

When explaining P4 for AC (D) at 9:51, the instructor says "valuable contributions implies that they are well-run", and you can replace Valuable with Well-run in P4 (seemingly from what we have in P1). So for P4 - (Large and Valuable --> Large and Well-run). So in AC (C), I have "zoos that make valuable contributions" - here, it can't mean "zoos that are well-run"?

"For several centuries there have been hairless dogs in western Mexico and in coastal Peru. It is very unlikely that a trait as rare as hairlessness emerged on two separate occasions. Since the dogs have never existed in the wild, and the vast mountainous jungle separating these two regions would have made overland travel between them extremely difficult centuries ago, the dogs must have been transported from one of these regions to the other by boat, probably during trading expeditions."

Conclusion: The dogs must have been transported from one of these regions to the other by boat, probably during trading expeditions.

• Support: The dogs have never existed in the wild, and the vast mountainous jungle separating these two regions would have made overland travel between them extremely difficult centuries ago.

Looking at the two popular ACs (negated):

A - Hairless dogs have at least once have been found anywhere except in the regions of western Mexico and coastal Peru —> ultimately, the conclusion talks about the dogs being transported between western Mexico and coastal Peru by boat. The fact that they may have been found elsewhere, does it impact the conclusion about the transport between those two countries? Not really.

E - Centuries ago it was NOT easier to travel between western Mexico and coastal Peru by boat as by an overland route. —> The implication is, that it was the travel was either as equally as hard or equally as easy (not one was easier/harder than the other). What does this mean?

• It wasn’t more difficult using overland route than by boat (like the premises state), it was either equally as hard or equally as easy. If this is the case, then why would you then conclude the dogs being brought to one of the countries from the other HAD to be by boat? Yes, the premises state that since “vast mountainous jungle separating these two regions would have made overland travel between them extremely difficult centuries ago” it had to be by boat, but if we assume that travelling by overland route was not any harder/easier than by boat, than you can’t really say with 100% certainty that it MUST HAVE BEEN by boat (and much less that it was during trading expedition)

 The higher the average fat intake among the residents of a country, the higher the incidence of cancer in that country; the lower the average fat intake, the lower the incidence of cancer. So individuals who want to reduce their risk of cancer should reduce their fat intake.

Premises: Average fat intake impacts incidence of cancer (higher AF leads to higher cancer incidence; lower AF leads to lower cancer incidence)

Conclusion: if you want to reduce risk of cancer you should reduce your fat intake.

!!! >>> Gap: average fat intake impacts RISK of cancer -> look for an AC that sort-of is related this idea somewhat (it's related to the conclusion).

The premises talked about incidence of cancer, whereas the conclusion talks about the RISK of cancer - two different ideas. Connecting the two gives you the notion that average fat intake impacts the RISK.

Looking at ACs A and B seem irrelevant. No mention of risk (or even hint).

Look at C and E:

• C: even if Cancer is a prominent cause of death in a country with a low average fat intake, it's also the case for a country with a high average fat intake. It doesn't explain the difference why in one instance it may be higher or lower.

• E: if someone is an outlier or a minority with respect to their low fat intake, that doesn't explain the difference.

Now, look at why AC "D" could work: country has high average fat intake, and higher incidence of cancer; but also high pollution. If you reduce the fat intake in this country [which is what supposedly we need to lower RISK of cancer], are you necessarily because of this lowering your risk of cancer? No, because your risk of cancer can still be high because of the pollution, even with lower average fat intake. So lowering your average fat intake, in this case, will not necessarily lower your risk of cancer.

For AC (A):

1 . X - good luck charm

2 . ABC used X. - AFS use charms

3 . ABC is Y. - AFS win lottery

_____

Conc: X leads to Y. - good luck charm leads to winning lottery

/F —> /SI } There is no individual freedom without social integrity

/GL —> /SI } Pursuing the good life is not possible without social integrity

________

/F —> /RL } There can be no individual freedom without the rule of law

Assumption: /F --> /SI —> /RL (we know that /F leads to /SI; how can we thus get from /SI to guarantee /RL? = hence, the assumption). The /GL (good life) component doesn't play a role in the argument/assumption.

I'm wondering, if you break down the parts:

1. "Any conceivable form of life depends on the presence of adequate amounts of chemical elements heavier than hydrogen and helium".

2. "Our sun has an unusually high abundance of these heavier elements for its age."

If we say that Statement #1 doesn't support Statement #2 (which makes (B) wrong and (A) right), then if we take #2 on its own, how would we know what "these heavier elements" that it's referring to? Sure, we don't know what those heavier elements are specifically, but we can infer they're heavier than something (by comparison). In the question, we know "these heavier elements" are those that are heavier than hydrogen and helium, without knowing what they are exactly. How, then, is #1 not supportive of #2?

If the question was "Conditions in our solar system have probably favored the emergence of life more than conditions in most other solar systems of similar age. Any conceivable form of life depends on the presence of adequate birds and insects in the solar system, and our sun has an unusually high abundance of these heavier elements for its age." then you can reasonably infer that Statements 1 and 2 are without evidence and independent of each other. But if there's an inferred comparison to something (even if it's not named), how does that not support the second statement?

Hi folks, this is kind of how I was able to determine the answer was (C) - this may help you:

• Conclusion: Most who filed did so as a "money-grab" so-to-speak --> They filed not because of a legitimate injury/didn't have a legitimate reason to/for filing late.

• What weakens this argument: there was a legitimate reason why the employees filed later, and not due to a "money-grab" (my word)

A) Workers cannot file for compensation for many job-related injuries, such as hearing loss from factory noise, until they have left the job. —> An employee has to wait until they leave the job to file a claim = Explains why they filed later (i.e. when they were fired) (not for a money grab). Weakens.

B) In the years before the factory closed, the factory's managers dismissed several employees who had filed injury claims. —> Before, the employees would risk getting fired by submitting a claim - they waited to be fired first (in other words - the factory closing) before submitting the claims, they didn't do it when they did to gain benefits they didn't deserve (not a money grab). Weakens.

C) Most workers who receive an injury on the job file for compensation on the day they suffer the injury. —> So if you normally file day after injury, why file after plant has closed (presumably more than a day after you were injured)? This could strengthen argument, that they applied later than they normally do, because they were out for money - POTENTIAL ANSWER (when analyzing each AC one by one)

D) Workers who incur partial disabilities due to injuries on the job often do not file for compensation because they would have to stop working to receive compensation but cannot afford to live on that compensation alone. —> Explains why workers filed the claims later (couldn't afford to stop working in order to receive the compensation) (not money grab). Weakens.

E) Workers who are aware that they will soon be laid off from a job often become depressed, making them more prone to job-related injuries. —> How does this weaken? Multiple injuries (due to expectation of being fired soon) may be the reason why the claims were submitted later, not because they were out for money. Weakens.

@KarlieS @ZulymarPerez the way I understand it is, that the conclusion is "The key to quitting, however, may be as simple as replacing an unhealthy activity with a healthy one." --> if you pick a random sample of smokers (without knowing any pre-existing conditions), your results are likely to be better representative of the program's effects than if you picked people who have dispositions to have/not have success.

For example, if you said the people in the first group were more likely to be diabetic, than the fact they didn't have success may stem from this condition and not the notion that they just didn't exercise. If you apply the random sampling idea, then you're kind of inferring that we're going off of people without any special/particular conditions (which may skew the results of your studies).

@Shannell_E'llan I hope it wasn't too confusing :D I wrote it out after watching the explanation.

"After hearing testimony establishing that Alaska Natives had made many uses of sea otters before the occupation of the territory by Russia in the late 1700s, the court reconsidered what constituted a traditional item under the statute. The court now held that the FWS's regulations were based on a "strained interpretation" of the word "traditional," and that the reference to "living memory" imposed an excessively restrictive time frame."

If we say that the court re-considered, (after hearing the testimony of Alaskan Natives made uses of sea otters before the occupation of territory by Russia in the late 1700s) and subsequently held the belief that the FWS's regulations were based on a "strained definition" of the words "traditional", given the context of the passage, how is it that we can say "well the court didn't cite to what the Natives said about tradition", therefore (A) is wrong? The court, after hearing the testimony from Alaskan Natives based on how THEY interpreted tradition (as well as their practices), defined the regulations as strained, because FWS didn't (seemingly) consider how Alaska Natives have historically understood tradition.

Cheers!

Is the idea here that, for A, we're talking about "plant or animal species", which are mentioned in the conclusion, whereas B talks about "world's most endangered species"? So we know from the conclusion that regular intervention by resource managers is needed to "maintain its fill complement of plant and animal species", but the stimulus doesn't suggest that regular interventions by resource managers is needed for endangered species. Because (I suppose), technically it's possible that plant and animal species aren't necessarily among the "world's most dangerous species", which would mean that the conclusion on its own is not linked to what B is saying, because stimulus links resource managers and plant and animal species, whereas option B links resource managers and endangered species. The stimulus doesn't say anything about endangered species not surviving without interventions.