QUES: Since the 1970s, an important focus of study has been the ozone layer in the atmosphere above Antarctica. In 1985, three British scientists working on data they had gathered at Halley Station on the Brunt Ice Shelf discovered the existence of a hole in this layer. It was eventually determined that the destruction of the ozone was caused by chlorofluorocarbons (CFCs) emitted by human products. With the ban of CFCs in the Montreal Protocol of 1989, climate projections indicate that the ozone layer will return to 1980 levels between 2050 and 2070.

What was studied in 1970?
What is the answer?
ANS: unanswerable
QUES: The legend of Virgil in his Basket arose in the Middle Ages, and is often seen in art and mentioned in literature as part of the Power of Women literary topos, demonstrating the disruptive force of female attractiveness on men. In this story Virgil became enamoured of a beautiful woman, sometimes described as the emperor's daughter or mistress and called Lucretia. She played him along and agreed to an assignation at her house, which he was to sneak into at night by climbing into a large basket let down from a window. When he did so he was only hoisted halfway up the wall and then left him trapped there into the next day, exposed to public ridicule. The story paralleled that of Phyllis riding Aristotle. Among other artists depicting the scene, Lucas van Leyden made a woodcut and later an engraving.

When did Lucas van Leyden live?
What is the answer?
ANS: unanswerable
QUES: Mean speeds vary greatly, but is typically around 1 m (3 ft) per day. There may be no motion in stagnant areas; for example, in parts of Alaska, trees can establish themselves on surface sediment deposits. In other cases, glaciers can move as fast as 2030 m (70100 ft) per day, such as in Greenland's Jakobshavn Isbr (Greenlandic: Sermeq Kujalleq). Velocity increases with increasing slope, increasing thickness, increasing snowfall, increasing longitudinal confinement, increasing basal temperature, increasing meltwater production and reduced bed hardness.

What makes some glaciers stagnant?
What is the answer?
ANS:
unanswerable