Hydrogen poses a number of hazards to human safety, from potential detonations and fires when mixed with air to being an asphyxiant in its pure, oxygen-free form. In addition, liquid hydrogen is a cryogen and presents dangers (such as frostbite) associated with very cold liquids. Hydrogen dissolves in many metals, and, in addition to leaking out, may have adverse effects on them, such as hydrogen embrittlement, leading to cracks and explosions. Hydrogen gas leaking into external air may spontaneously ignite. Moreover, hydrogen fire, while being extremely hot, is almost invisible, and thus can lead to accidental burns.
What can hydrogen embrittlement lead to?
cracks and explosions


Input: Modern history
Starting one-hundred years before the 20th century, the enlightenment spiritual philosophy was challenged in various quarters around the 1900s. Developed from earlier secular traditions, modern Humanist ethical philosophies affirmed the dignity and worth of all people, based on the ability to determine right and wrong by appealing to universal human qualities, particularly rationality, without resorting to the supernatural or alleged divine authority from religious texts. For liberal humanists such as Rousseau and Kant, the universal law of reason guided the way toward total emancipation from any kind of tyranny. These ideas were challenged, for example by the young Karl Marx, who criticized the project of political emancipation (embodied in the form of human rights), asserting it to be symptomatic of the very dehumanization it was supposed to oppose. For Friedrich Nietzsche, humanism was nothing more than a secular version of theism. In his Genealogy of Morals, he argues that human rights exist as a means for the weak to collectively constrain the strong. On this view, such rights do not facilitate emancipation of life, but rather deny it. In the 20th century, the notion that human beings are rationally autonomous was challenged by the concept that humans were driven by unconscious irrational desires.

When was the enlightenment of spiritual philosophy challenged?
Output: in various quarters around the 1900s.


Input: Article: The staple foods were generally consumed around 11 o'clock, and consisted of bread, lettuce, cheese, fruits, nuts, and cold meat left over from the dinner the night before.[citation needed] The Roman poet Horace mentions another Roman favorite, the olive, in reference to his own diet, which he describes as very simple: "As for me, olives, endives, and smooth mallows provide sustenance." The family ate together, sitting on stools around a table. Fingers were used to eat solid foods and spoons were used for soups.[citation needed]

Now answer this question: When were the staple foods in the Roman republic typically eaten at?

Output: 11 o'clock


Article: Gaddafi financially supported other militant groups across the world, including the Black Panther Party, Nation of Islam, Tupamaros, 19th of April Movement and Sandinista National Liberation Front in the Americas, the ANC among other liberation movements in the fight against Apartheid in South Africa, the Provisional Irish Republican Army, ETA, Sardinian nationalists, Action directe, the Red Brigades, and the Red Army Faction in Europe, and the Armenian Secret Army, Japanese Red Army, Free Aceh Movement, and Moro National Liberation Front in Asia. Gaddafi was indiscriminate in the causes he funded, sometimes switching from supporting one side in a conflict to the other, as in the Eritrean War of Independence. Throughout the 1970s these groups received financial support from Libya, which came to be seen as a leader in the Third World's struggle against colonialism and neocolonialism. Though many of these groups were labelled "terrorists" by critics of their activities, Gaddafi rejected such a characterisation, instead considering them revolutionaries engaged in liberation struggles.

Question: What was the Third World fighting against in the 1970s?
Ans: colonialism and neocolonialism


Here is a question about this article: In 1797, Patrick Colquhoun was able to persuade the West Indies merchants who operated at the Pool of London on the River Thames, to establish a police force at the docks to prevent rampant theft that was causing annual estimated losses of £500,000 worth of cargo. The idea of a police, as it then existed in France, was considered as a potentially undesirable foreign import. In building the case for the police in the face of England's firm anti-police sentiment, Colquhoun framed the political rationale on economic indicators to show that a police dedicated to crime prevention was "perfectly congenial to the principle of the British constitution." Moreover, he went so far as to praise the French system, which had reached "the greatest degree of perfection" in his estimation.
What is the answer to this question: How much cargo had been being stolen from West Indies merchants in London each year?
****
So... £500,000


Article: A similar situation occurs with waders (called shorebirds in North America). Many species, such as dunlin Calidris alpina and western sandpiper Calidris mauri, undertake long movements from their Arctic breeding grounds to warmer locations in the same hemisphere, but others such as semipalmated sandpiper C. pusilla travel longer distances to the tropics in the Southern Hemisphere.

Question: Where do dunlin Calidris alpina migrate to?
Ans:
warmer locations in the same hemisphere