16Hit1600
Expression of IdeasEasy–MediumRhetorical synthesis (using notes to explain an advantage)

Expression of Ideas practice question

While researching a topic, a student has taken the following notes: • Qanats are gently sloping underground tunnels that carry water from mountain aquifers to dry lowlands. • The oldest known qanats in Iran date to roughly 1000 BCE. • Some qanats extend for more than 40 kilometers. • Water moving through a qanat stays underground, so very little of it evaporates. • Open surface canals in hot, dry regions can lose a large share of their water to evaporation.

The student wants to explain an advantage that qanats have over surface canals. Which choice most effectively uses relevant information from the notes to accomplish this goal?

  1. A. Qanats are gently sloping underground tunnels that carry water from mountain aquifers to dry lowlands, and some of them extend for more than 40 kilometers.
  2. B. Because a qanat carries water through an underground tunnel rather than an open channel, it loses far less water to evaporation than a surface canal does in a hot, dry region.Correct
  3. C. The oldest known qanats in Iran date to roughly 1000 BCE, well before surface canals were built in the region.
  4. D. Surface canals in hot, dry regions can lose a large share of their water to evaporation, and some qanats extend for more than 40 kilometers.

Answer: B. Because a qanat carries water through an underground tunnel rather than an open channel, it loses far less water to evaporation than a surface canal does in a hot, dry region.

B is correct: it names the relevant feature of qanats (water travels underground) and states the resulting benefit relative to surface canals (much less evaporation), which is exactly the requested comparison. A is a definition plus a length detail; it never mentions surface canals or any advantage. C substitutes chronology for advantage and also adds a claim about when surface canals were built that the notes do not support. D pairs a fact about surface canals with an unrelated fact about qanat length, so the two halves do not form a comparison of advantages.

Why the other answers are wrong

A. Qanats are gently sloping underground tunnels that carry water from mountain aquifers to dry lowlands, and some of them extend for more than 40 kilometers.
This defines qanats and adds their length, but it never mentions surface canals or states any advantage over them.
C. The oldest known qanats in Iran date to roughly 1000 BCE, well before surface canals were built in the region.
Age isn't an advantage, and the notes never say when surface canals were built in the region, so that comparison is unsupported.
D. Surface canals in hot, dry regions can lose a large share of their water to evaporation, and some qanats extend for more than 40 kilometers.
The two halves don't connect: evaporation loss in surface canals is paired with qanat length rather than with the underground feature that prevents evaporation.

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