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On June 17, 2015, 21-year-old Dylann Roof entered the historic Emanuel African Methodist Episcopal Church during a Bible study and killed nine people. Senior pastor Clementa Pinckney, who also served as a state senator, was among those killed during the attack. The deceased also included congregation members Susie Jackson, 87; Rev. Daniel Simmons Sr., 74; Ethel Lance, 70; Myra Thompson, 59; Cynthia Hurd, 54; Rev. Depayne Middleton-Doctor, 49; Rev. Sharonda Coleman-Singleton, 45; and Tywanza Sanders, 26. The attack garnered national attention, and sparked a debate on historical racism, Confederate symbolism in Southern states, and gun violence. On July 10, 2015, the Confederate battle flag was removed from the South Carolina State House. A memorial service on the campus of the College of Charleston was attended by President Barack Obama, Michelle Obama, Vice President Joe Biden, Jill Biden, and Speaker of the House John Boehner.
Clementa Pinckney served what public office for the state of South Carolina?
A: state senator

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One result of debates over the meaning and validity of the concept of race is that the current literature across different disciplines regarding human variation lacks consensus, though within some fields, such as some branches of anthropology, there is strong consensus. Some studies use the word race in its early essentialist taxonomic sense. Many others still use the term race, but use it to mean a population, clade, or haplogroup. Others eschew the concept of race altogether, and use the concept of population as a less problematic unit of analysis.
What is a less problematic unit of analysis?
A: concept of population

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The history of the area that now constitutes Himachal Pradesh dates back to the time when the Indus valley civilisation flourished between 2250 and 1750 BCE. Tribes such as the Koilis, Halis, Dagis, Dhaugris, Dasa, Khasas, Kinnars, and Kirats inhabited the region from the prehistoric era. During the Vedic period, several small republics known as "Janapada" existed which were later conquered by the Gupta Empire. After a brief period of supremacy by King Harshavardhana, the region was once again divided into several local powers headed by chieftains, including some Rajput principalities. These kingdoms enjoyed a large degree of independence and were invaded by Delhi Sultanate a number of times. Mahmud Ghaznavi conquered Kangra at the beginning of the 10th century. Timur and Sikander Lodi also marched through the lower hills of the state and captured a number of forts and fought many battles. Several hill states acknowledged Mughal suzerainty and paid regular tribute to the Mughals.
Who marched through the lower states and captured and forts and fought many battles?
A: Timur and Sikander Lodi

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Purely electronic circuit elements soon replaced their mechanical and electromechanical equivalents, at the same time that digital calculation replaced analog. The engineer Tommy Flowers, working at the Post Office Research Station in London in the 1930s, began to explore the possible use of electronics for the telephone exchange. Experimental equipment that he built in 1934 went into operation 5 years later, converting a portion of the telephone exchange network into an electronic data processing system, using thousands of vacuum tubes. In the US, John Vincent Atanasoff and Clifford E. Berry of Iowa State University developed and tested the Atanasoff–Berry Computer (ABC) in 1942, the first "automatic electronic digital computer". This design was also all-electronic and used about 300 vacuum tubes, with capacitors fixed in a mechanically rotating drum for memory.
How many vacuum tubes did the Atanasoff-Berry computer use?
A:
about 300