This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
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Question: Passage: Antibiotics are screened for any negative effects on humans or other mammals before approval for clinical use, and are usually considered safe and most are well tolerated. However, some antibiotics have been associated with a range of adverse side effects. Side-effects range from mild to very serious depending on the antibiotics used, the microbial organisms targeted, and the individual patient. Side effects may reflect the pharmacological or toxicological properties of the antibiotic or may involve hypersensitivity reactions or anaphylaxis. Safety profiles of newer drugs are often not as well established as for those that have a long history of use. Adverse effects range from fever and nausea to major allergic reactions, including photodermatitis and anaphylaxis. Common side-effects include diarrhea, resulting from disruption of the species composition in the intestinal flora, resulting, for example, in overgrowth of pathogenic bacteria, such as Clostridium difficile. Antibacterials can also affect the vaginal flora, and may lead to overgrowth of yeast species of the genus Candida in the vulvo-vaginal area. Additional side-effects can result from interaction with other drugs, such as elevated risk of tendon damage from administration of a quinolone antibiotic with a systemic corticosteroid. Some scientists have hypothesized that the indiscriminate use of antibiotics alter the host microbiota and this has been associated with chronic disease. Question: What is one possible serious side effect of over-using antibiotics?

Answer: alter the host microbiota


Question: Passage: Downtown Boston's streets grew organically, so they do not form a planned grid, unlike those in later-developed Back Bay, East Boston, the South End, and South Boston. Boston is the eastern terminus of I-90, which in Massachusetts runs along the Massachusetts Turnpike. The elevated portion of the Central Artery, which carried most of the through traffic in downtown Boston, was replaced with the O'Neill Tunnel during the Big Dig, substantially completed in early 2006. Question: What year was the O'neill tunnel put in place?

Answer: 2006


Question: Passage: On 26 June 1950, the National Assembly supported a crucial bill written by Milovan Đilas and Tito about "self-management" (samoupravljanje): a type of cooperative independent socialist experiment that introduced profit sharing and workplace democracy in previously state-run enterprises which then became the direct social ownership of the employees. On 13 January 1953, they established that the law on self-management was the basis of the entire social order in Yugoslavia. Tito also succeeded Ivan Ribar as the President of Yugoslavia on 14 January 1953. After Stalin's death Tito rejected the USSR's invitation for a visit to discuss normalization of relations between two nations. Nikita Khrushchev and Nikolai Bulganin visited Tito in Belgrade in 1955 and apologized for wrongdoings by Stalin's administration. Tito visited the USSR in 1956, which signaled to the world that animosity between Yugoslavia and USSR was easing. However, the relationship between the USSR and Yugoslavia would reach another low in the late 1960s. Commenting on the crisis, Tito concluded that: Question: Whose invitation did Tito reject after Stalin's death?

Answer:
USSR