Input: Article: Only Umayyad ruler (Caliphs of Damascus), Umar ibn Abd al-Aziz, is unanimously praised by Sunni sources for his devout piety and justice. In his efforts to spread Islam he established liberties for the Mawali by abolishing the jizya tax for converts to Islam. Imam Abu Muhammad Adbullah ibn Abdul Hakam stated that Umar ibn Abd al-Aziz also stopped the personal allowance offered to his relatives stating that he could only give them an allowance if he gave an allowance to everyone else in the empire. Umar ibn Abd al-Aziz was later poisoned in the year 720. When successive governments tried to reverse Umar ibn Abd al-Aziz's tax policies it created rebellion.

Now answer this question: In what year did Umar ibn Ad Al-Aziz die?

Output: 720

Input: Article: One way of proving that a given disease is "infectious", is to satisfy Koch's postulates (first proposed by Robert Koch), which demands that the infectious agent be identified only in patients and not in healthy controls, and that patients who contract the agent also develop the disease. These postulates were first used in the discovery that Mycobacteria species cause tuberculosis. Koch's postulates can not be applied ethically for many human diseases because they require experimental infection of a healthy individual with a pathogen produced as a pure culture. Often, even clearly infectious diseases do not meet the infectious criteria. For example, Treponema pallidum, the causative spirochete of syphilis, cannot be cultured in vitro - however the organism can be cultured in rabbit testes. It is less clear that a pure culture comes from an animal source serving as host than it is when derived from microbes derived from plate culture. Epidemiology is another important tool used to study disease in a population. For infectious diseases it helps to determine if a disease outbreak is sporadic (occasional occurrence), endemic (regular cases often occurring in a region), epidemic (an unusually high number of cases in a region), or pandemic (a global epidemic).

Now answer this question: What is Koch's second postulate?

Output: patients who contract the agent also develop the disease

Input: Article: A number of technologies allow asphalt/bitumen to be mixed at much lower temperatures. These involve mixing with petroleum solvents to form "cutbacks" with reduced melting point, or mixtures with water to turn the asphalt/bitumen into an emulsion. Asphalt emulsions contain up to 70% asphalt/bitumen and typically less than 1.5% chemical additives. There are two main types of emulsions with different affinity for aggregates, cationic and anionic. Asphalt emulsions are used in a wide variety of applications. Chipseal involves spraying the road surface with asphalt emulsion followed by a layer of crushed rock, gravel or crushed slag. Slurry seal involves the creation of a mixture of asphalt emulsion and fine crushed aggregate that is spread on the surface of a road. Cold-mixed asphalt can also be made from asphalt emulsion to create pavements similar to hot-mixed asphalt, several inches in depth and asphalt emulsions are also blended into recycled hot-mix asphalt to create low-cost pavements.

Now answer this question: What does mixing bitumen with water create?

Output:
emulsion