Beyond the answers - interesting background to this quiz

The table that took shape over decades

Dmitri Mendeleev is credited with the periodic table, but he was not working in a vacuum. Earlier chemists, including Antoine Lavoisier and John Dalton, had already laid groundwork by defining elements and atomic weights. What set Mendeleev's version apart, published in 1869, was that he left gaps for elements not yet discovered and predicted their properties. When those elements were later found, his arrangement earned lasting acceptance.

A storm that has lasted for centuries

Jupiter's Great Red Spot is a giant anticyclonic storm, wider than Earth at its largest observed extent. Records of it go back to the 17th century, though today it appears to be shrinking. Despite its size, Jupiter is a gas giant with no solid surface to stand on. The storm's reddish colour is still not fully explained, but it may involve chemical compounds brought up from deeper in the atmosphere.

The ocean's top predator

The sperm whale is the largest predator on Earth, hunting deep-sea squid in the dark. It locates prey using echolocation - clicks that bounce off objects and return as echoes. Its enormous head houses the spermaceti organ, which is thought to play a role in diving and sound production. Polar bears and great white sharks are formidable hunters, but neither matches the sperm whale's size.

Two cities, two continents

Dhaka, the capital of Bangladesh, sits on the Buriganga River and ranks among the world's most densely populated cities. Lusaka, Zambia's capital, lies on a high plateau in southern Africa and grew from a small railway settlement. Both capitals anchor their countries' political and economic life, though they differ sharply in climate, history and setting.

One novelist, many adventures

Alexandre Dumas wrote The Count of Monte Cristo and the d'Artagnan Romances, which include The Three Musketeers. His swashbuckling plots, filled with revenge, loyalty and duels, made him one of the most widely read French authors of the 19th century. He often worked with collaborators and drew on historical figures, turning them into enduring adventure heroes.