Problem: Following a steady decline, beginning in the late 1990s up through the mid-2000s, illicit drug use among adolescents has been on the rise in the U.S. Aside from alcohol, marijuana is the most commonly indulged drug habit during adolescent years. Data collected by the National Institute on Drug Abuse shows that between the years of 2007 and 2011, marijuana use grew from 5.7% to 7.2% among 8th grade students; among 10th grade students, from 14.2% to 17.6%; and among 12th graders, from 18.8% to 22.6%. Additional, recent years have seen a surge in popularity of MDMA; between 2010 and 2011, the use of MDMA increased from 1.4% to 2.3% among high school seniors. The heightened usage of ecstasy most likely ties in at least to some degree with the rising popularity of rave culture.
What is the most commonly abused substance during adolescent years in the U.S.?
---
Answer: alcohol

Problem: The BCG vaccine has limitations, and research to develop new TB vaccines is ongoing. A number of potential candidates are currently in phase I and II clinical trials. Two main approaches are being used to attempt to improve the efficacy of available vaccines. One approach involves adding a subunit vaccine to BCG, while the other strategy is attempting to create new and better live vaccines. MVA85A, an example of a subunit vaccine, currently in trials in South Africa, is based on a genetically modified vaccinia virus. Vaccines are hoped to play a significant role in treatment of both latent and active disease.
What does one option propose adding to the existing BCG vaccine?
---
Answer: subunit vaccine

Problem: An upgrade to Windows 8 known as Windows 8.1 was officially announced by Microsoft on May 14, 2013. Following a presentation devoted to the upgrade at Build 2013, a public beta version of the upgrade was released on June 26, 2013. Windows 8.1 was released to OEM hardware partners on August 27, 2013, and released publicly as a free download through Windows Store on October 17, 2013. Volume license customers and subscribers to MSDN Plus and TechNet Plus were initially unable to obtain the RTM version upon its release; a spokesperson said the policy was changed to allow Microsoft to work with OEMs "to ensure a quality experience at general availability." However, after criticism, Microsoft reversed its decision and released the RTM build on MSDN and TechNet on September 9, 2013.
When was Windows 9.1 introduced?
---
Answer:
unanswerable