LSAT 103 – Section 1 – Question 19

LSAT 103 - Section 1 - Question 19

September 1998

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT103 S1 Q19
+LR
+Exp
Most strongly supported +MSS
Conditional Reasoning +CondR
A
0%
154
B
1%
161
C
97%
165
D
2%
154
E
1%
152
129
137
145
 +Easier 147.884 +SubsectionMedium

Sponges attach to the ocean floor, continually filtering seawater for food and ejecting water they have just filtered to avoid reingesting it. Tubular and vase-shaped sponges can eject filtered water without assistance from surrounding ocean currents and thus are adapted to slow-moving, quiet waters. Because of their shape, however, these sponges cannot live in strong currents, since strong currents would dislodge them. Both of these varieties of sponge were widespread during the late Jurassic period.

Summary
Sea sponges live on the ocean floor and feed by filtering water. Two sponge types (tubular sponges and vase-shaped sponges) can filter feed without help from the current, so they do well in quiet waters. They also can’t live in stronger currents, because they would be dislodged from the ocean floor. Finally, both tubular and vase-shaped sponges were widespread in the late Jurassic period.

Strongly Supported Conclusions
These facts strongly support the conclusion that the late Jurassic period had many areas of ocean floor with slow currents, thus allowing tubular and vase-shaped sponges to be widespread. They also support the conclusion that areas with slow currents can still have enough fresh water moving through for sponges to find food.

A
Few tubular or vase-shaped sponges lived before the late Jurassic period.
Like (B), this is not supported. The only period covered by the stimulus is the late Jurassic: we don’t know what conditions were like for sponges, or how many sponges were around, either before or after.
B
Tubular and vase-shaped sponges were more common during the late Jurassic period than in succeeding geological eras.
Like (A), this is not supported. Because the facts only apply to the late Jurassic period, we can’t draw any conclusions about other periods, either before or after.
C
During the late Jurassic period there were many areas of the ocean floor where currents were weak.
This is strongly supported. The facts tell us that tubular and vase-shaped sponges can only live on the ocean floor where the current is weak. So, for them to be widespread during the late Jurassic period, there had to be widespread areas of the ocean floor with weak currents.
D
All sponges that are neither tubular nor vase-shaped inhabit areas of the ocean floor where there are extremely strong currents.
This is not supported. The author only discusses tubular and vase-shaped sponges; we learn nothing about other kinds of sponges. We don’t even know if there are other sponges, let alone what environmental conditions they prefer.
E
No types of sponge live in large colonies, since sponges do not flourish in areas where much of the water has been filtered by other sponges.
This is not supported. The stimulus doesn’t directly discuss sponge colonies, and we also cannot infer this from what we do know. We just don’t have enough detail about sponges’ filter feeding to know whether a sponge in a colony could still access enough food to flourish.

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Section 1 - Logical Reasoning

Section 2 - Logical Reasoning

Section 3 - Logical Reasoning

Section 4 - Reading Comprehension

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