In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Q: What vehicle could you have that you would need lower pressure boiler feed water?, Context: The Rankine cycle and most practical steam engines have a water pump to recycle or top up the boiler water, so that they may be run continuously. Utility and industrial boilers commonly use multi-stage centrifugal pumps; however, other types are used. Another means of supplying lower-pressure boiler feed water is an injector, which uses a steam jet usually supplied from the boiler. Injectors became popular in the 1850s but are no longer widely used, except in applications such as steam locomotives.

A: steam locomotives
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Q: What isn't good enough?, Context: A third type of solution to the problem of the direction of time, although much less represented, argues that the laws are not time-reversal symmetric. For example, certain processes in quantum mechanics, relating to the weak nuclear force, are not time-reversible, keeping in mind that when dealing with quantum mechanics time-reversibility comprises a more complex definition. But this type of solution is insufficient because 1) the time-asymmetric phenomena in quantum mechanics are too few to account for the uniformity of macroscopic time-asymmetry and 2) it relies on the assumption that quantum mechanics is the final or correct description of physical processes.[citation needed]

A: A third type of solution to the problem of the direction of time, although much less represented, argues that the laws are not time-reversal symmetric
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Q: Which happened later, the typhoons of 1671 or the smallpox epidemic?, Context: Intermittent warfare lasting from July 23, 1670 until July 1695, plus the typhoons of 1671 and 1693, and in particular the smallpox epidemic of 1688, reduced the Chamorro population from 50,000 to 10,000 to less than 5,000.:86 Precipitated by the death of Quipuha, and the murder of Father San Vitores and Pedro Calungsod by local rebel chief Matapang, tensions led to a number of conflicts. Captain Juan de Santiago started a campaign to pacify the island, which was continued by the successive commanders of the Spanish forces.:68–74

A:
the smallpox epidemic
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