Here is a question about this article: Other sources include fortified food and dietary supplements, which come in various forms. A 1998 review concluded that zinc oxide, one of the most common supplements in the United States, and zinc carbonate are nearly insoluble and poorly absorbed in the body. This review cited studies which found low plasma zinc concentrations after zinc oxide and zinc carbonate were consumed compared with those seen after consumption of zinc acetate and sulfate salts. However, harmful excessive supplementation is a problem among the relatively affluent, and should probably not exceed 20 mg/day in healthy people, although the U.S. National Research Council set a Tolerable Upper Intake of 40 mg/day.
What is the answer to this question: What is the most common supplement in the US?
****
So... zinc oxide

The problem: Answer a question about this article:
Nunzia Rondanini stated, "Through its aesthetic dimension architecture goes beyond the functional aspects that it has in common with other human sciences. Through its own particular way of expressing values, architecture can stimulate and influence social life without presuming that, in and of itself, it will promote social development.'
What does architecture share with other sciences?
****
The answer: functional aspects

Problem: Please answer a question about the following article about Premier League:
At the inception of the Premier League in 199293, just eleven players named in the starting line-ups for the first round of matches hailed from outside of the United Kingdom or Ireland. By 200001, the number of foreign players participating in the Premier League was 36 per cent of the total. In the 200405 season the figure had increased to 45 per cent. On 26 December 1999, Chelsea became the first Premier League side to field an entirely foreign starting line-up, and on 14 February 2005 Arsenal were the first to name a completely foreign 16-man squad for a match. By 2009, under 40% of the players in the Premier League were English.
On which date did Chelsea host an entirely foreign starting line-up and therefore become the first team to do so?
A: 26 December 1999

Question: Read this and answer the question

But early in the 16th century, a brilliant new red appeared in Europe. When the Spanish conquistador Hernan Cortes and his soldiers conquered the Aztec Empire in 1519-1521, they discovered slowly that the Aztecs had another treasure beside silver and gold; they had the tiny cochineal, a parasitic scale insect which lived on cactus plants, which, when dried and crushed, made a magnificent red. The cochineal in Mexico was closely related to the Kermes varieties of Europe, but unlike European Kermes, it could be harvested several times a year, and it was ten times stronger than the Kermes of Poland. It worked particularly well on silk, satin and other luxury textiles. In 1523 Cortes sent the first shipment to Spain. Soon cochineal began to arrive in European ports aboard convoys of Spanish galleons.

Which conquistador from Spain conquered the Aztec Empire?
Answer: Hernan Cortes

Problem: By the 1500s, Ismail I from Ardabil, established the Safavid Dynasty, with Tabriz as the capital. Beginning with Azerbaijan, he subsequently extended his authority over all of the Iranian territories, and established an intermittent Iranian hegemony over the vast relative regions, reasserting the Iranian identity within large parts of the Greater Iran. Iran was predominantly Sunni, but Ismail instigated a forced conversion to the Shia branch of Islam, by which the Shia Islam spread throughout the Safavid territories in the Caucasus, Iran, Anatolia, and Mesopotamia. As a result, thereof, the modern-day Iran is the only official Shia nation of the world, with it holding an absolute majority in Iran and the Republic of Azerbaijan, having there the 1st and 2nd highest number of Shia inhabitants by population percentage in the world.
What country is currently the only official Shia nation of the world?
The answer is the following: Iran

Input: Article: Tibet was once a strong power contemporaneous with Tang China (618907). Until the Tibetan Empire's collapse in the 9th century, it was the Tang's major rival in dominating Inner Asia. The Yarlung rulers of Tibet also signed various peace treaties with the Tang, culminating in a treaty in 821 that fixed the borders between Tibet and China.

Now answer this question: What year did Tang and Tibet sign a treaty to fix the borders?

Output:
821