Biologist: Marine animals known

Answer choices

1. A

   Too Strong1% picked this

   Box jellyfish are the only kind of jellyfish with retinas that do

   Too Strong: only Only Thing Mentioned ? Only Thing The author hasn't committed to this extreme claim that the only jellyfish with retinas that don't focus clearly are box jellyfish. The argument only mentions box jellyfish, but we're never accusing the author of assuming that the only X mentioned is therefore the only X. Otherwise, we'd accuse people who say "Black lives matter" of thinking that "Black lives are the only kind of lives that matter".

   1%
2. B

   Correct91% picked this

   Box jellyfish have a need to detect prominent features of objects but

   Why this is right

   This is one of the two missing links we predicted, based on these New Concepts in the conclusion. The author is concluding that the box jellyfish's vision is adapted only to its needs not to an ideal standard, since its vision can detect prominent features of objects in blurry focus but not in fine detail. So the author must be assuming that the box jellyfish's needs stop at "being able to see prominent features" and that's why it never evolved all the way to fine detail. If we negated this and said, "Box jellyfish have a need to detect prominent features and fine details" then that would utterly destroy the argument. There's no way we could conclude that its vision is adapted to its needs, if it needs fine details but its vision doesn't provide fine details.

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

   91%
3. C

   Out of Scope: benefit4% picked this

   Box jellyfish would benefit from having retinas that allowed their eyes to

   Nothing in this argument is about whether or not a given thing would benefit an animal. If we negate this answer and say, "They wouldn't benefit from retinas that allow their eyes to focus more sharply", that wouldn't weaken the argument. In the author's mind, the fact that the box jellyfish's vision doesn't provide sharp focus shows that the box jellyfish doesn't need sharp focus. So if our negation were saying, "Hey, author -- the box jellyfish wouldn't even benefit from sharp focus", that wouldn't go against anything she's arguing. Whether we "need" something is a totally different inquiry than whether something would benefit us.

   4%
4. D

   Opposite, if anything1% picked this

   Box jellyfish developed from jellyfish whose retinas received

   The notion of what the box jellyfish evolved from is really out of scope. The author is just claiming that creatures evolve according to their needs, not according to ideal design. This answer is saying, "The author must assume that box jellyfish evolved from a species with more ideal design". That would actually seem more like a weakening idea than anything. The author thinks that the evolution of the box jellyfish's visual system stopped at "being able to make out prominent objects" and never evolved all the way to sharp focus / fine detail / clear images, because the box jellyfish didn't need vision that good. So if anything the author would probably think that the evolutionary predecessor of the box jellyfish had similar or worse vision.

   1%
5. E

   Out of Scope3% picked this

   Box jellyfish use vision as their main means of

   Out of Scope: detecting prey Too Strong: main We have no idea how the box jellyfish detects prey; we never talked about such a thing. There's no reason to think the author has committed to any idea about what is the box jellyfish's #1 means of detecting prey.

   3%