Beyond the answers - interesting background to this quiz

Landlocked countries and the sea they never see

Austria is one of the world's landlocked countries, meaning it has no coastline at all. It borders eight countries, including Germany, Italy and Switzerland, but the nearest sea lies well beyond its borders. Landlocked status shapes trade, tourism and even naval history: such countries have sometimes maintained river flotillas instead of fleets. Around the world, dozens of nations share this situation, from Bolivia in South America to Nepal in Asia.

The Maya and their enduring world

The Maya lived across a broad region of Mesoamerica, including parts of present-day Honduras, Guatemala, Belize and southern Mexico. They built cities such as Tikal and Copán, developed a written script and made remarkable advances in astronomy and mathematics, including the use of zero. Their civilisation was never a single empire but a network of competing city-states. Millions of Maya descendants still live in the region today, speaking dozens of Mayan languages.

Morocco's languages beyond Arabic

Arabic is the official language of Morocco, but the country's linguistic landscape is far richer than that single fact suggests. Moroccan Arabic, known as Darija, is the everyday spoken variety and differs noticeably from the Arabic of the Middle East. Tamazight, the language of the Amazigh (Berber) people, gained official status in 2011, and French remains widely used in business and education. Spanish is also common in the north, a legacy of geography and history.

The coulomb and the flow of charge

The coulomb is the unit of electric charge, named after the French physicist Charles-Augustin de Coulomb, who studied the forces between charges. One coulomb is a surprisingly large amount of charge - roughly the charge carried by a lightning bolt's brief flash. The ampere, by contrast, measures the rate of flow of charge, so one ampere equals one coulomb passing a point each second. The ohm, meanwhile, measures resistance, completing the trio of units that describe basic electrical circuits.

Hydrogen: the simplest element in the universe

Hydrogen has atomic number 1, meaning its nucleus contains a single proton. It is the lightest and most abundant element in the universe, and stars like our Sun fuse hydrogen into helium to release energy. On Earth it rarely appears alone, instead bonding with oxygen to form water or with carbon in fuels. Its simplicity has made it central to chemistry and to debates about clean energy.