The eligible age-range for contestants is currently fifteen to twenty-eight years old. The initial age limit was sixteen to twenty-four in the first three seasons, but the upper limit was raised to twenty-eight in season four, and the lower limit was reduced to fifteen in season ten. The contestants must be legal U.S. residents, cannot have advanced to particular stages of the competition in previous seasons (varies depending on the season, currently by the semi-final stage until season thirteen), and must not hold any current recording or talent representation contract by the semi-final stage (in previous years by the audition stage).
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): When was the age limit increased to 28?
Ah, so.. season four

Hydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 7000100794000000000♠1.00794 u, hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass.[note 1] Non-remnant stars are mainly composed of hydrogen in its plasma state. The most common isotope of hydrogen, termed protium (name rarely used, symbol 1H), has one proton and no neutrons.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is the atomic weight for hydrogen?
Ah, so.. 7000100794000000000♠1.00794 u

Ben Goldacre has argued that regulators – such as the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK, or the Food and Drug Administration (FDA) in the United States – advance the interests of the drug companies rather than the interests of the public due to revolving door exchange of employees between the regulator and the companies and friendships develop between regulator and company employees. He argues that regulators do not require that new drugs offer an improvement over what is already available, or even that they be particularly effective.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Who argues that regulators do not require that new regulators offer an improvement?
Ah, so..
unanswerable