Problem: Red:

Red clothing was a sign of status and wealth. It was worn not only by cardinals and princes, but also by merchants, artisans and townpeople, particularly on holidays or special occasions. Red dye for the clothing of ordinary people was made from the roots of the rubia tinctorum, the madder plant. This color leaned toward brick-red, and faded easily in the sun or during washing. The wealthy and aristocrats wore scarlet clothing dyed with kermes, or carmine, made from the carminic acid in tiny female scale insects, which lived on the leaves of oak trees in Eastern Europe and around the Mediterranean. The insects were gathered, dried, crushed, and boiled with different ingredients in a long and complicated process, which produced a brilliant scarlet.

Outside of sun exposure in what circumstance did pigment made from rubia tinctorum fade?
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A: during washing

Problem: Vacuum:

Ion gauges are used in ultrahigh vacuum. They come in two types: hot cathode and cold cathode. In the hot cathode version an electrically heated filament produces an electron beam. The electrons travel through the gauge and ionize gas molecules around them. The resulting ions are collected at a negative electrode. The current depends on the number of ions, which depends on the pressure in the gauge. Hot cathode gauges are accurate from 103 torr to 1010 torr. The principle behind cold cathode version is the same, except that electrons are produced in a discharge created by a high voltage electrical discharge. Cold cathode gauges are accurate from 102 torr to 109 torr. Ionization gauge calibration is very sensitive to construction geometry, chemical composition of gases being measured, corrosion and surface deposits. Their calibration can be invalidated by activation at atmospheric pressure or low vacuum. The composition of gases at high vacuums will usually be unpredictable, so a mass spectrometer must be used in conjunction with the ionization gauge for accurate measurement.

What affects the number of ions in a gauge?
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A: the pressure in the gauge

Problem: Alloy:

Although an alloy is technically an impure metal, when referring to alloys, the term "impurities" usually denotes those elements which are not desired. These impurities are often found in the base metals or the solutes, but they may also be introduced during the alloying process. For instance, sulfur is a common impurity in steel. Sulfur combines readily with iron to form iron sulfide, which is very brittle, creating weak spots in the steel. Lithium, sodium and calcium are common impurities in aluminium alloys, which can have adverse effects on the structural integrity of castings. Conversely, otherwise pure-metals that simply contain unwanted impurities are often called "impure metals" and are not usually referred to as alloys. Oxygen, present in the air, readily combines with most metals to form metal oxides; especially at higher temperatures encountered during alloying. Great care is often taken during the alloying process to remove excess impurities, using fluxes, chemical additives, or other methods of extractive metallurgy.

Using fluxes and chemical additives during the alloying process does what?
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A: remove excess impurities

Problem: Mexico City:

The Legislative Assembly of the Federal District is formed, as it is the case in all legislatures in Mexico, by both single-seat and proportional seats, making it a system of parallel voting. The Federal District is divided into 40 electoral constituencies of similar population which elect one representative by first-past-the-post plurality (FPP), locally called "uninominal deputies". The Federal District as a whole constitutes a single constituency for the parallel election of 26 representatives by proportionality (PR) with open-party lists, locally called "plurinominal deputies".

What is the local government of Mexico City called?
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A:
The Legislative Assembly of the Federal District