Local resident: An overabundance of algae

Answer choices

1. A

   Not Assumed: more susceptible4% picked this

   presumes, without providing justification, that smaller fish are somehow more susceptible to harm as a result of overabundant

   Since this answer starts with presumes / takes for granted, we ask ourselves whether the author was assuming the idea that follows. The author never discusses larger fish, nor does she say anything comparative in relation to small vs. large fish. The fact that she only mentions small fish being harmed doesn't mean that she thinks only small fish are harmed (or that they're harmed more). If we negate this supposed assumption and say, "Actually, author, larger fish are just as susceptible to harm from algae as are smaller fish", that doesn't weaken the argument. The author could still be totally correct that algae is harming the smaller fish.

   4%
2. B

   Not an Objection1% picked this

   fails to consider that the effects on smaller fish of overabundant algae may be less severe in larger bodies of

   Not an Objection: other bodies of water Since this answer starts with fails to consider / overlooks the possibility, we ask ourselves whether the idea that follows would weaken. Would it hurt the argument if we said, "Hey, author - smaller fish wouldn't be as severely affected by high algae if this were a larger body of water"? Nope, that's totally out of scope. The author is only trying to convince us that in this body of water, the pond, an abundance of algae is harming smaller fish.

   1%
3. C

   Not an Objection: other size fish2% picked this

   ignores the possibility that the same cause might have different effects on fish

   Since this answer starts with fails to consider / ignores the possibility, we ask ourselves whether the idea that follows would weaken. Would it hurt the argument if we said, "Hey, author - that high amount of algae would have different effects on medium or larger size fish"? Nope, that's totally out of scope. The author is only trying to convince us that a high amount of algae is harming the smaller fish in this pond. What it does to other fish is not relevant.

   2%
4. D

   Correct93% picked this

   ignores the possibility that the overabundance of algae and the deaths of smaller fish are independent effects

   Why this is right

   Since this answer starts with fails to consider / ignores the possibility, we ask ourselves whether the idea that follows would weaken. Would it hurt the argument if we said, "Hey, author - it's possible that the high algae and dead small fish are both effects of some common cause"? Yes, that would be an Alternate Explanation, specifically the one we nickname "Third Factor". Whenever an author looks at a correlation between X and Y and then concludes that X causes Y, we always have two alternate explanations to reflexively consider: 1. could it be reverse cause? It is possible that Y is causing X, and that's why they're correlated? 2. could it be a third factor? It is possible that Z is causing both X and Y, and that's why X and Y are correlated? Maybe when the weather is too warm, it both creates a lot of algae and kills smaller fish. That would be a common cause that would account for why this author sees lots of algae and dead small fish occur at the same time.

   Skill tested: Flaw · how this choice captures the argument's function is the move to repeat next time.

   93%
5. E

   Not an Objection: scarcity of algae1% picked this

   ignores the possibility that below-normal amounts of algae are detrimental to the

   Since this answer starts with fails to consider / ignores the possibility, we ask ourselves whether the idea that follows would weaken. Would it hurt the argument if we said, "Hey, author - a very small amount of algae can be bad for smaller fish"? Not really. We might be tempted to think that we're undermining the author's claim that "big amounts of algae are harmful to smaller fish" by saying that "small amounts of algae are harmful to smaller fish", but it's very compatible for both things to be true. Very low amounts of solar radiation (sunlight) are bad for humans and so are very high amounts of solar radiation. It's coherent to think that both too much and too little of a given thing can be harmful.

   1%