Physical Geography — Global Desert Coverage Tropical and temperate deserts together occupy approximately what fraction of the Earth’s land surface (rounded, school-level figure)?
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A(1/4)
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B(1/3)
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C(1/2)
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D(1/7)
Answer
Correct Answer: (1/3)
Explanation
Introduction / Context:Deserts (arid and semi-arid categories are often separated, but school-level summaries typically aggregate “tropical and temperate deserts”) cover a notable share of Earth’s land. Being able to recall the approximate fraction helps in understanding climate zones, biome distribution, and human settlement patterns.
Given Data / Assumptions:
- We use a rounded, commonly cited textbook value.
- “Deserts” here refers to arid regions with very low precipitation; some sources include semi-arid margins.
- The question expects an order-of-magnitude fraction rather than an exact percentage.
Concept / Approach:Across major continental interiors and subtropical high-pressure belts, deserts such as the Sahara, Arabian, Gobi, Kalahari, Australian, Atacama, and deserts of North America occupy a substantial fraction of land. Standard primers round this to “about one-third” of Earth’s land surface when grouping tropical and temperate deserts together.
Step-by-Step Solution:
Recall widely taught figure for total desert coverage on land.Match numeric fraction to verbal statement: “about one-third.”Select the option written as (1/3).Reject more extreme or smaller values that do not align with textbooks.Verification / Alternative check:Many school atlases and geography texts cite values near 30–33% for deserts and semi-deserts combined, which corresponds to roughly one-third.
Why Other Options Are Wrong:
- (1/4): Underestimates when semi-desert margins are included.
- (1/2): Overestimates land under deserts.
- (1/7): Considerably too low.
Common Pitfalls:Confusing “desert” strictly with sand seas; many deserts are rocky or gravelly and still count toward arid coverage.
Final Answer:(1/3)