Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Naturally occurring glass, especially the volcanic glass obsidian, has been used by many Stone Age societies across the globe for the production of sharp cutting tools and, due to its limited source areas, was extensively traded. But in general, archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or ancient Egypt. The earliest known glass objects, of the mid third millennium BCE, were beads, perhaps initially created as accidental by-products of metal-working (slags) or during the production of faience, a pre-glass vitreous material made by a process similar to glazing.
What kind of glass exists in nature?
A: obsidian

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Many public high schools are located in the borough including the elite Bronx High School of Science, Celia Cruz Bronx High School of Music, DeWitt Clinton High School, High School for Violin and Dance, Bronx Leadership Academy 2, Bronx International High School, the School for Excellence, the Morris Academy for Collaborative Study, Wings Academy for young adults, The Bronx School for Law, Government and Justice, Validus Preparatory Academy, The Eagle Academy For Young Men, Bronx Expeditionary Learning High School, Bronx Academy of Letters, Herbert H. Lehman High School and High School of American Studies. The Bronx is also home to three of New York City's most prestigious private, secular schools: Fieldston, Horace Mann, and Riverdale Country School.
Where is the DeWitt Clinton High School?
A: The Bronx

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The Quran assumes familiarity with major narratives recounted in the Biblical scriptures. It summarizes some, dwells at length on others and, in some cases, presents alternative accounts and interpretations of events. The Quran describes itself as a book of guidance. It sometimes offers detailed accounts of specific historical events, and it often emphasizes the moral significance of an event over its narrative sequence. The Quran is used along with the hadith to interpret sharia law. During prayers, the Quran is recited only in Arabic.
Which scientific text calls itself a book of guidance?
A: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
He tells that during this time he ran into a friend who told him that he was teaching Transcendental Meditation (TM), which prompted Schwarzenegger to reveal he had been struggling with anxiety for the first time in his life: "Even today, I still benefit from [the year of TM] because I don't merge and bring things together and see everything as one big problem."
What psychological problem did Schwarzenegger say he struggled with?
A:
anxiety