Beyond the answers - interesting background to this quiz

The noble gas that kept its Greek name

Xenon takes its name from the Greek word xenos, meaning "stranger" or "foreigner", a fitting label for an element that is famously unreactive. It belongs to the noble gases, the group at the far right of the periodic table whose members rarely bond with other elements. Despite that reputation, xenon does form compounds under special conditions, and it has practical uses in high-intensity lamps and as an anaesthetic.

The race to crack the double helix

Watson and Crick's model of DNA, published in 1953, rested heavily on experimental work done by others, above all the X-ray diffraction images produced by Rosalind Franklin and Maurice Wilkins. Franklin's famous Photograph 51 gave crucial evidence of DNA's helical structure. She died in 1958, four years before the Nobel Prize was awarded to Watson, Crick and Wilkins, and Nobel rules do not allow posthumous nominations.

The river that crosses six countries

The Mekong begins on the Tibetan Plateau and runs through China, Myanmar, Laos, Thailand, Cambodia and Vietnam before emptying into the South China Sea. It supports one of the most productive freshwater fisheries in the world and provides food and income for millions of people. Dams built along its course, particularly in China and Laos, have raised ongoing concerns about the river's flow and ecology.

Why Nepal draws mountaineers

Nepal contains eight of the world's ten highest mountains, including Everest, which sits on its border with Tibet. The country's geography ranges from the low, humid Terai plains to the high Himalayas within a relatively short distance. That combination makes it a magnet for trekkers and climbers, and mountaineering tourism is a major part of its economy.

Nostradamus and the business of prophecy

Nostradamus was a sixteenth-century French physician and astrologer whose collection of cryptic verses, the Centuries, has been mined for predictions ever since. The quatrains are deliberately vague and mix languages and imagery, which makes them easy to match to later events after the fact. That flexibility, rather than any proven foresight, is why his name still turns up whenever something dramatic happens.