instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: A single-replacement reaction is one in which an element replaces another element in a compound. An element is in either the solid, liquid, or gas state and is not an ion. The example below shows the reaction of solid magnesium metal with aqueous silver nitrate to form aqueous magnesium nitrate and silver metal. Answer: single-replacement reaction
answer:
In this type of reaction, an element replaces another element in a compound, and the element is in any state of matter but is not an ion?

question:
Passage: Figure 12.7 Statues made from carbonate compounds such as limestone and marble typically weather slowly over time due to the actions of water, and thermal expansion and contraction. However, pollutants like sulfur dioxide can accelerate weathering. As the concentration of air pollutants increases, deterioration of limestone occurs more rapidly. (credit: James P Fisher III). Answer: air pollutants
answer:
Deterioration of limestone occurs more rapidly as the concentration of what increases?

question:
Passage: The Karakoram Range is part of the Himalaya Mountains. K2, pictured here, is the second highest mountain the world at over 28,000 feet. The number and height of mountains is impressive. Answer: k2
answer:
What is the second highest mountain in the world, at over 28,000 feet?