In modern deep-diving

Answer choices

1. A

   No Impact4% picked this

   Some deep-diving marine species must surface after dives but do not have bones with

   It would hurt this argument to talk about things that had porous bones but don't deep sea dive, but this answer is talking about things that deep sea dive but don't have porous bones.

   4%
2. B

   No Impact1% picked this

   In most modern marine reptile species, the outer shell of the bones

   We don't care whether porous outer bones is something most modern marine reptiles have or don't have. We care about whether deep sea diving is a trait that most marine reptiles with porous bones have or don't have.

   1%
3. C

   Correct76% picked this

   In most modern and prehistoric marine reptile species that are not deep divers, the outer shell of

   Why this is right

   This would weaken even more if it were phrased, "for most modern and prehistoric marine reptile species that have porous outer bones, they are not deep-divers". But this still weakens by showing us that there are many examples of a prehistoric marine reptiles that have porous bones but don't deep dive. It makes it seem more speculative to go from knowing Ichthyosaur has porous bones to assuming it was a deep diver. It also suggests that these marine reptiles are evolving porous bones for a different reason than to aid with deep diving (since most non-deep divers have them).

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

   76%
4. D

   No Impact14% picked this

   In addition to the porous outer shells of their bones, whales have at least some characteristics suited to deep diving for which there is

   This could have potentially worked if it said, "whales have other qualities suited for deep diving, but ichthyosaurs don't have those other things". Since this instead just says "there's no clear evidence" we have no idea whether ichthyosaurs did or didn't share these other traits.

   14%
5. E

   No Impact5% picked this

   There is evidence that the bones of ichthyosaurs would have been light enough to allow surfacing even if the

   There's a little distortion in terms here. The porous outer bones make it easy to surface. This answer choice is talking about whether their bones are light enough to allow them to surface. No one ever implied that ichthyosaurs need porous bones to surface, just that having porous bones makes it easier to surface.

   5%