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Question

Difficulty: EasyComprehending Explicit Comparisons and Contrasts

Passage Excerpt:
Glaciers move across landscapes through two primary mechanisms: basal sliding and internal deformation. Basal sliding occurs when liquid water under immense pressure acts as a lubricant beneath the glacier, allowing the entire ice mass to melt slightly at its base and slide over bedrock. In contrast, internal deformation occurs when individual ice crystals within the glacier slip past one another under the weight of overlying ice without requiring subglacial liquid water. While basal sliding dominates in warmer temperate glaciers where basal ice reaches the melting point, internal deformation is the principal movement mechanism in cold polar glaciers, where the ice remains frozen solid to the bedrock below.

Based on the passage, what is one explicitly stated difference between basal sliding and internal deformation?

  1. Basal sliding requires subglacial liquid water to facilitate movement, whereas internal deformation occurs without requiring subglacial liquid water.Answer
  2. B
    Basal sliding occurs when ice crystals slip past one another under heavy weight, whereas internal deformation relies on melting ice at the bedrock surface.
  3. C
    Basal sliding serves as the primary movement mechanism in cold polar glaciers, whereas internal deformation predominates in warmer temperate glaciers.
  4. D
    Basal sliding enables glaciers to travel across bedrock, whereas internal deformation causes glaciers to remain completely motionless.

Answer

Basal sliding requires subglacial liquid water to facilitate movement, whereas internal deformation occurs without requiring subglacial liquid water.
The correct option accurately reflects the passage's explicit contrast: basal sliding relies on subglacial liquid water acting as a lubricant, whereas internal deformation involves ice crystals slipping past one another without needing subglacial liquid water.

Step-by-Step Solution

1
Locate the explicit statements regarding basal sliding and internal deformation in the passage.
Found that basal sliding occurs when 'liquid water... acts as a lubricant beneath the glacier', while internal deformation happens 'without requiring subglacial liquid water'.
Direct comparison questions require finding the explicitly stated contrasting details for both mechanisms.
2
Compare the located facts with the provided choices.
The option stating that basal sliding requires subglacial liquid water while internal deformation does not directly mirrors the explicit contrast made in the passage.
Matching explicit passage facts ensures accurate selection without introducing invalid inferences.

Key Concept

Comprehending Explicit Comparisons and Contrasts
Estimated Time:1m 0s
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Topics

Comprehending Explicit Comparisons and Contrasts

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