Beyond the answers - interesting background to this quiz

The river that gave a country its name

The Indus is one of the longest rivers in Asia, rising in the Tibetan plateau and flowing through India before reaching Pakistan, where it empties into the Arabian Sea near Karachi. Its name is the root of both "India" and "Hindustan", and the Indus Valley Civilisation, one of the world's earliest urban cultures, grew up along its banks. Today the river is central to Pakistan's agriculture, feeding an extensive irrigation system.

A young capital with an ancient past

Skopje sits on the Vardar River and has been inhabited for thousands of years, passing through Roman, Byzantine and Ottoman hands. It became the capital of the Socialist Republic of Macedonia within Yugoslavia after the Second World War, and remained the capital when North Macedonia declared independence in 1991. A devastating earthquake in 1963 destroyed much of the city centre, which was rebuilt in a distinctly modernist style.

Why O negative matters in an emergency

Blood is classified by the ABO system and the presence or absence of the Rh factor. O negative red cells carry neither A nor B antigens nor the Rh antigen, so they can generally be given to patients of any blood type, which makes them vital in emergencies when there is no time to test. Because O negative donors are relatively uncommon, blood services often appeal specifically for them.

The web versus the internet

The internet - a network of connected computers - existed for decades before the World Wide Web arrived. Tim Berners-Lee developed the web at CERN in 1989 as a way to share documents between researchers, and the first website went live in 1991. The key innovation was linking documents together with hypertext, which turned a technical network into something anyone could browse.

Andersen's darker fairy tales

Hans Christian Andersen published The Little Match Girl in 1845, and it is far bleaker than the stories most readers associate with him. Andersen wrote for both children and adults, and many of his tales, including The Little Mermaid and The Snow Queen, carry melancholy or moral weight beneath their surface charm. His work has been translated into more than a hundred languages.