Beyond the answers - interesting background to this quiz

The rarest naturally occurring element on Earth

Astatine, symbol At, sits at number 85 on the periodic table and is famously the rarest naturally occurring element in the Earth's crust. It is radioactive, with a half-life measured in hours, so any sample that exists is vanishing almost as soon as it appears. It was first produced artificially in 1940, and even today the total amount present in the crust at any moment is estimated to be under 30 grams. That is one reason it is a favourite answer in chemistry quizzes.

A continent's highest point, far from the Alps

Aconcagua, in Argentina, is the highest peak in the Americas and the highest outside Asia, rising to roughly 6,961 metres in the Andes. Despite its height, it is considered a non-technical climb by mountaineering standards, which is why it attracts thousands of trekkers each season. It sits close to the Chilean border, which is why Chile often appears as a tempting wrong answer.

The lake shared by three nations

Lake Victoria is Africa's largest lake by surface area and the source of the White Nile. Its waters are shared by Tanzania, Uganda and Kenya, making it one of the few major lakes divided among three countries. It supports one of the world's largest freshwater fisheries, though that ecosystem has been heavily altered by introduced species.

Roman numerals in the wild

LXXX is 80: L for 50, plus three X's for 30. Roman numerals still appear on clock faces, film credits, monument dates and the occasional tattoo, so recognising them remains a genuinely useful skill. The trick is simple: when a smaller numeral follows a larger one, you add; when it precedes, you subtract.

Hemingway's posthumous novel

The Garden of Eden was published in 1986, a quarter of a century after Ernest Hemingway's death, in an edited form drawn from a much longer manuscript. It is one of several late works that appeared posthumously and shows a different side of him from the hunting and war stories he is best known for. The Great Gatsby, of course, belongs to F. Scott Fitzgerald, not Hemingway.