Examkin

Question

Difficulty: MediumLogical Inferences

Planetary scientists studying Mars note that its deuterium-to-hydrogen (D/HD/H) atmospheric ratio is five times higher than Earth's. Because deuterium is heavier, light hydrogen escapes Mars's gravity more easily, elevating this ratio over time. However, satellite observations show that during dust storms, water vapor is lofted to high altitudes where ultraviolet radiation breaks it apart. Since these storms occur sporadically and solar activity fluctuates, scientists hypothesize that hydrogen loss is highly variable. Consequently, when a major dust storm coincides with peak solar activity, which increases ultraviolet levels, ______

Which choice most logically completes the text?

  1. A
    deuterium will begin to escape the atmosphere at a faster rate than light hydrogen.
  2. B
    Mars's atmospheric D/HD/H ratio will rapidly decrease to match Earth's ratio.
  3. the rate of hydrogen escaping into space will likely experience a temporary surge.Answer
  4. D
    the frequency of global dust storms on Mars will begin to align with the cycles of solar activity.

Answer

the rate of hydrogen escaping into space will likely experience a temporary surge.
The correct option is supported because the passage establishes that global dust storms loft water vapor to high altitudes where ultraviolet radiation dissociates it, and that solar activity levels influence the rate of hydrogen loss. If a major storm occurs during peak solar activity, the abundance of water vapor at high altitudes combined with elevated ultraviolet levels will naturally lead to a temporary increase in the dissociation rate and a subsequent surge in hydrogen escape.

Step-by-Step Solution

1
Identify the direct consequences of dust storms on Martian water vapor as described in the passage.
Dust storms loft water vapor to high altitudes where ultraviolet (UV) radiation breaks it apart, releasing hydrogen.
Understanding how water vapor is transported and dissociated is key to determining when hydrogen becomes free to escape.
2
Analyze the impact of peak solar activity on this process.
Peak solar activity increases ultraviolet levels, which will increase the rate at which UV radiation breaks apart the lofted water vapor.
Connecting solar activity to the chemical breakdown of water vapor explains how the rate of hydrogen release is affected.
3
Combine the effects of both events occurring simultaneously to draw a logical conclusion.
When a major dust storm lofts abundant water vapor high into the atmosphere and peak solar activity provides high levels of UV radiation, the breakdown of water vapor accelerates, causing a temporary surge in the rate of hydrogen escaping into space.
Synthesizing the two conditions leads to the only logical, non-speculative outcome supported by the premises.

Key Concept

Logical Inferences
Estimated Time:1m 30s
Rate this question

Topics

Logical Inferences

More questions from this topic