Beyond the answers - interesting background to this quiz

A grain that fooled the botanists

Quinoa is often called a pseudocereal because it is not a true cereal grain like wheat or rice. It belongs to the amaranth family, and the part we eat is actually the seed. The plant was domesticated thousands of years ago in the Andean region of South America, where it still grows at high altitude. Its protein profile is unusually complete for a plant food, which is why it attracts so much attention from nutritionists.

Why the liver has a second job

Bile is produced in the liver and then stored and concentrated in the gallbladder before being released into the small intestine. Its main role is to break large fat droplets into smaller ones, a process called emulsification, which makes fats easier for enzymes to digest. The liver performs hundreds of other tasks as well, from filtering blood to storing glycogen, which is why it can regenerate after partial damage.

The day the Bastille fell

On 14 July 1789, a crowd in Paris stormed the Bastille, a fortress and prison that had come to symbolise royal authority. Although only a handful of prisoners were held there at the time, the event became a turning point in the French Revolution. Its anniversary is still marked in France as Bastille Day, known there as la Fête nationale.

The river that drains a fifth of Asia

The Yangtze, also called the Chang Jiang or "Long River", is the longest river in Asia and the third longest in the world. It rises on the Tibetan Plateau and travels roughly 6,300 kilometres before reaching the sea near Shanghai. Along the way it passes through the Three Gorges, supports huge populations and carries enormous volumes of freight, making it one of the busiest waterways on Earth.

Barium and the limits of a single letter

The chemical symbol for barium is Ba, not B. That single letter is already taken by boron, and the periodic table has no room for duplicates. Barium sits in the alkaline earth metal group, alongside calcium and magnesium, and its compounds have long been used in medicine as a contrast agent for imaging the digestive tract.