- PowerScore Staff
- Posts: 8948
- Joined: Feb 02, 2011
- Thu Apr 07, 2016 7:23 pm
#22858
Complete Question Explanation
Must Be True. The correct answer choice is (C)
The key to answering this question quickly and efficiently is to focus solely on those facts that can be put together to form a logically valid inference. Much of the information here is redundant and merely meant to delay you. Quite simply, since tubular and vase-shaped sponges are only adapted to slow-moving waters and cannot thrive in strong currents, it is reasonable to infer that any period during which such sponges are particularly widespread must be characterized by slow-moving waters:
Answer choice (A): The stimulus provides no evidence as to what variety of sponges lived before the late Jurassic period. This answer choice is incorrect.
Answer choice (B): The stimulus provides no evidence as to what variety of sponges lived after the end of the Jurassic period. It is entirely plausible that succeeding geological eras had even weaker currents. This answer choice is incorrect.
Answer choice (C): This is the correct answer choice. See discussion above.
Answer choice (D): Just because tubular and vase-shaped sponges only inhabit areas with weak currents does not mean that all other varieties of sponges inhabit areas with strong currents. It is entirely possible that some types of sponges can live anywhere, regardless of how strong or weak the currents are. This answer choice is a Mistaken Negation of the conditional relationship between tubular/vase-shaped sponges and weak currents.
Answer choice (E): Whether the colonies in which sponges live are large or small is not a fact that is easily inferable from the stimulus. It is entirely possible that some waters contain virtually limitless amount of food that cannot be depleted of nutrients no matter how many sponges are filtering it.
Must Be True. The correct answer choice is (C)
The key to answering this question quickly and efficiently is to focus solely on those facts that can be put together to form a logically valid inference. Much of the information here is redundant and merely meant to delay you. Quite simply, since tubular and vase-shaped sponges are only adapted to slow-moving waters and cannot thrive in strong currents, it is reasonable to infer that any period during which such sponges are particularly widespread must be characterized by slow-moving waters:
- Tubular/Vase Sponges → Slow-Moving Waters
Answer choice (A): The stimulus provides no evidence as to what variety of sponges lived before the late Jurassic period. This answer choice is incorrect.
Answer choice (B): The stimulus provides no evidence as to what variety of sponges lived after the end of the Jurassic period. It is entirely plausible that succeeding geological eras had even weaker currents. This answer choice is incorrect.
Answer choice (C): This is the correct answer choice. See discussion above.
Answer choice (D): Just because tubular and vase-shaped sponges only inhabit areas with weak currents does not mean that all other varieties of sponges inhabit areas with strong currents. It is entirely possible that some types of sponges can live anywhere, regardless of how strong or weak the currents are. This answer choice is a Mistaken Negation of the conditional relationship between tubular/vase-shaped sponges and weak currents.
Answer choice (E): Whether the colonies in which sponges live are large or small is not a fact that is easily inferable from the stimulus. It is entirely possible that some waters contain virtually limitless amount of food that cannot be depleted of nutrients no matter how many sponges are filtering it.
