LR Question 26 Explanation
QUESTION TEXT: All oceangoing ships carry seawater ballast tanks…
QUESTION TYPE: Necessary Assumption
CONCLUSION: We could stop ballast environmental damage by emptying and refilling ballast tanks in midocean.
REASONING: Oceangoing ships’ ballast tanks need to be emptied. This can cause environmental damage, because ships’ ballast tanks can transport sea creatures from one environment to another. In a new environment, sea creatures can cause environmental harm.
However, sea creatures from the coast usually can’t survive in midocean environments, and vice-versa.
ANALYSIS: There’s no way around it; this is a long question. But don’t panic. When you see a long question, it’s more time effective to slow down and understand it. If you know all the facts in the reasoning above, this question is easy. It’s entering the answers with poor understanding that causes slowness and errors.
The conclusion is that the midocean method is viable. That means it actually has to work, but the stimulus didn’t give us any information on that point. So a necessary assumption is that ships can actually use this method.
(There is a difference between a plan, and a plan that works. For instance, in theory we could get resources from the moon. In practice, we don’t yet have the technology that would make those trips economically viable. The midocean ballast plan is just a plan. Whereas the conclusion is that it’s a viable plan, and the author has given no evidence on whether the plan could actually work.)
___________
- This is a very tempting answer. But it’s a trap. Midocean creatures may be very capable of disturbing other midocean habitats. However, that’s irrelevant, because the stimulus says that the midocean creatures usually can’t survive in the coastal environments where they will be dumped.
- This makes the argument harder to prove. It certainly isn’t necessary.
- We already know that oceangoing ships can cause environmental harm by transferring sea creatures. Whether or not sea creatures can cause harm by other methods is irrelevant.
- This isn’t necessary. There could be other times that ships pump ballasts, as long as ships aren’t forced to transfer ballast from one coastal environment to another. (or one midocean environment to another)
- CORRECT. If this isn’t true, then the plan is impossible.
Negation: No oceangoing ships are able to maintain stability while pumping ballast in midocean.
The sheer number of comments on this question shows how poor of a question it is lol.
Definitely agree it’s one of the ones I dislike!
“…the stimulus says that the midocean creatures can’t survive in the coastal environments where they will be dumped.”
Isn’t this false? It says the “usually” can’t survive, not that they can’t.
I eliminated A because it was way too strong a claim; we don’t need to “ensure” that no creatures capable of disturbing the ecology are pumped into the tanks, and “disturbing” the ecology is a much lower bar than “wreak[ing] ecological havoc” — maybe even their presence could constitute a disturbance. We also don’t care about all habitats in the argument, just coastal vs mid-ocean.
Beyond that, it is also self-contradictory, because as you point out, mid-ocean creatures could still disturb other mid-ocean habitats. Lots of reasons why A is bad.
E is clearly the best answer, but I am having some trouble with C. It was clearly between these two options for me.
According to the stimulus:
Problem: [ sea creatures deposited into habitats where they can wreak ecological havoc ]
Viable way to address problem: [ empty/refill at sea, since coastal/midocean sea creatures usually cannot survive in each other’s habitats]
From the stimulus, I was expecting an answer that related surviving to wreaking ecological havoc (since if they don’t need to survive to wreak havoc, the entire argument falls apart] and this was very close.
“We already know that oceangoing ships can cause environmental harm by transferring sea creatures. Whether or not sea creatures can cause harm by other methods is irrelevant.”
I don’t see any mention about harm by other methods involved with C? We know that the ships cause environmental harm by transferring the sea creatures, because those creatures can wreak havoc on their new habitats.
There were two reasons eliminated this answer: 1) the scope was too large: the argument doesn’t rely on “all” sea creatures not wreaking havoc in “all” new habitats, only of “mid ocean and coastal” sea creatures being able to wreak havoc in one another’s habitats. 2) the qualifier “after being deposited by ocean going ships” was not specified in the argument, and is too specific; the claim in the last sentence doesn’t make any mention of the method by which the creatures end up in one another’s environment, only that they generally cannot survive in them.
You’re absolutely right that the passage says coastal and mid-ocean creatures USUALLY can’t survive in each other’s habitats, rather than making an absolute claim. However, this doesn’t affect the reasoning behind eliminating A. Whether some creatures survive isn’t the key issue, because the argument is primarily concerned with long-term ecological harm, not short-term disturbances.
On C, your instinct was correct. It seems tempting, but it’s ultimately too broad and too specific at the same time. The argument is focused on one method of species transfer (ballast tanks) so the assumption must relate to that context, but C makes a broader claim about ALL cases of ecological harm caused by sea creatures. So C goes beyond what the argument requires. The reasoning doesn’t depend on why a species was deposited, just whether the mid-ocean exchange will effectively prevent harm.
E is necessary because if ships can’t actually empty and refill ballast tanks while maintaining stability, the entire plan fails. Hopefully that clarifies it!
For A, wouldn’t the negation wreck the argument? Sea creatures capable of wreaking ecological havoc? Yes, they can’t survive, but we don’t know how long it takes to wreak havoc, and it doesn’t seem that unreasonable to assume a dead body could wreak some havoc.
Apologies for the late response, but still wanted to address this. The key issue with A is that even if some mid-ocean creatures could wreak havoc before dying, it wouldn’t undermine the argument. The core assumption is that the proposed solution is viable (meaning ships can actually carry it out). Whether or not a few creatures cause short-term disruption before dying is a separate issue and doesn’t affect the feasibility of the plan itself.
Negating A would mean that some transferred creatures are capable of causing harm. But since the stimulus already acknowledges that ecological harm occurs and argues that the real problem is long-term survival in a new environment, the argument still holds.
In contrast, negating E (showing that no ship can maintain stability while using this method) would make the plan impossible. So that’s why E is necessary and A isn’t. Hope that helps!
For E, how do we know that the ships must be able to maintain stability at all times? We are only told that the seawater ballast tanks IMPROVE stability, not that stability is necessary. Maybe stability is merely helpful with turning the ship or something and is not necessary to have when the ship is emptying and refilling ballast tanks. I get why the other answer choices are worse, but I get tripped up on questions like these because the correct answer doesn’t seem like a truly requires answer to me.
It’s because E says “adequalely” maintained. If you don’t maintain adequate stability, then you have inadequate stability. That suggests either the boat doesn’t move or it sinks.
It’s not a stretch to assert that ships need to be stable. You’re allowed and even required to use common sense on the LSAT. If everyone would agree with a statement then you can use it.
Note: This is an old comment but I wanted to clarify the point.
If I empty the tank and refill it mid-ocean, go to port, unload cargo, subsequently go out to sea and empty the tanks before refilling again, I may be introducing sea creatures from one mid-ocean habitat into another, and those sea creatures may wreak havoc on this new habitat. You confirm this by saying “midocean creatures may be very capable of disturbing other midocean habitats.”
The problem we are trying to fix is that “sea creatures often get into tanks and are then inadvertently deposited into new habitats, where they can wreak ecological havoc.”
Given the above, I cannot convince myself that A is not a necessary assumption. You say that A is irrelevant because “the stimulus says that the mid-ocean creatures can’t survive in the coastal environments where they will be dumped.” Two things. First, It doesn’t say they will be dumped in coastal environments. Second, so? What does that have to do with non-native mid-ocean sea creatures wreaking havoc on other mid-ocean habitats? If non-native mid-ocean sea creatures wreak ecological havoc due to emptying tanks in the middle of the ocean rather than on the coast, how is our problem solved?
If A is not necessary, you are simply moving the ecological havoc from the coast to mid-ocean; you still have the issue of sea creatures possibly getting into tanks and later wreaking havoc in other habitats.
Please show me where I am wrong.
You bring up two good points. But, I think there are equally good counters to them both:
(1) We’re told that water must be pumped in and pumped out in order to counteract the effect of unloading and loading cargo. We can make the common sense assumption that the cargo will be loaded and unloaded in coastal environments, because ports are generally located on the coast or shore. So, we know that there’s a very good chance the mid-ocean creatures will be dumped out in coastal environments.
(2) This one contradicts the stimulus. We’re told that coastal creatures usually can’t survive mid-ocean environments.
So, is it really necessary to ensure that mid-ocean creatures won’t be dumped in other mid-ocean environments? It’s possible that some mid-ocean creatures might survive the pumping out of water at port, but it’s a stretch to say that this is necessary for our argument. Also, remember, we’re looking for the best possible answer choice. If we pit the negation of (A) against the negation of (E), it’s very easy to make the case that the latter is a much stronger counter to the argument in the stimulus.
Doesn’t the argument require that if sea creatures don’t survive in a habitat, they cannot create ecological damage?
And isn’t C saying that?
Here’s how to draw C:
Damage possible –> Creature deposited in habitat by oceangoing ship and creature can survive there
This is broader than what you’re saying. You could negate this answer, but still leave your statement true. (i.e. the negation is: “damage is possible even without ships” That has no impact on the statement “damage –> survival possible”)
Hi Graeme,
I was wondering whether it would be possible to elaborate some on (C).
The stimulus says that sea creatures (presumably from one coast when the ship is going through one half of the loading/unloading process) “get into the tanks and are then inadvertently deposited into new habitats” (at the next coast/docking place). This constitutes a “coast to coast” transfer of sea creatures “where they can wreak ecological havoc”. The solution the stimulus offers is to empty out the tanks and refill them mid-ocean so the coastal creatures spit out mid-ocean die and the new creatures sucked up mid-ocean then die when they reach the next coast. The whole plans seems to rest on the idea that by putting them somewhere where they cannot survive they will not “wreck ecological havoc” as they would in a place where they could survive.
The negation of (C), I believe, states that sea creatures can sometimes (side question: what exactly is the negation of rarely?) wreck ecological havoc in a new habitat even if they do not survive in that habitat after having been deposited there. Considering the stimulus’ conclusion is also a “can” (as opposed to a “for now they definitely do”) how is this not a necessary assumption? If they can theoretically wreck havoc just as easily either way then what’s the point?
I can wholly see how (E) is necessary I just got caught up on (C).