Problem: Ann Arbor was founded in 1824, named for wives of the village's founders and the stands of Bur Oak trees. The University of Michigan moved from Detroit to Ann Arbor in 1837, and the city grew at a rapid rate in the early to mid-20th century. During the 1960s and 1970s, the city gained a reputation as a center for left-wing politics. Ann Arbor became a focal point for political activism and served as a hub for the civil-rights movement and anti-Vietnam War movement, as well as various student movements.
During  the 1960's & 70's, Ann Arbor gained a reputation for what?
The answer is the following: center for left-wing politics

Problem: In lossy audio compression, methods of psychoacoustics are used to remove non-audible (or less audible) components of the audio signal. Compression of human speech is often performed with even more specialized techniques; speech coding, or voice coding, is sometimes distinguished as a separate discipline from audio compression. Different audio and speech compression standards are listed under audio coding formats. Voice compression is used in internet telephony, for example, audio compression is used for CD ripping and is decoded by the audio players.
What is used in internet telephony? 
The answer is the following: Voice compression

Problem: Game players were not the only ones to notice the violence in this game; US Senators Herb Kohl and Joe Lieberman convened a Congressional hearing on December 9, 1993 to investigate the marketing of violent video games to children.[e] While Nintendo took the high ground with moderate success, the hearings led to the creation of the Interactive Digital Software Association and the Entertainment Software Rating Board, and the inclusion of ratings on all video games. With these ratings in place, Nintendo decided its censorship policies were no longer needed.
Which senators held a hearing about video game violence in 1993?
The answer is the following: Herb Kohl and Joe Lieberman

Problem: This may be managed directly on an individual basis, or by the assignment of individuals and privileges to groups, or (in the most elaborate models) through the assignment of individuals and groups to roles which are then granted entitlements. Data security prevents unauthorized users from viewing or updating the database. Using passwords, users are allowed access to the entire database or subsets of it called "subschemas". For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data. If the DBMS provides a way to interactively enter and update the database, as well as interrogate it, this capability allows for managing personal databases.
What does data security avoid?
The answer is the following:
unauthorized users from viewing or updating the database