Beyond the answers - interesting background to this quiz

The planet that keeps rewriting its own surface

Earth's terrain is unusually varied because several forces work on it at once. Plate tectonics builds mountains and opens ocean basins, while wind, water and ice slowly wear the land down. Unlike the Moon or Mercury, Earth also has an atmosphere and flowing water, which shape coastlines, rivers and deserts. Venus and Mars are fascinating worlds, but neither matches this range of landforms.

A statue that watches over Rio

Christ the Redeemer stands on the peak of Corcovado, a granite mountain rising above Rio de Janeiro. The statue was completed in 1931 and its outstretched arms span roughly 28 metres. It is regularly struck by lightning, and the local archdiocese keeps a stock of the same soapstone used for its outer layer to carry out repairs.

The instrument that looks like a string player but is not

The flute belongs to the woodwind family, not the strings. A string instrument makes sound when a stretched string vibrates, either with a bow or by plucking. The cello and violin both work this way, which is why they sit together in an orchestra's string section. The flute instead produces sound from a column of air moving across an opening.

From boy band to solo fame

Robbie Williams first became known as a member of Take That, the British pop group formed in Manchester in the early 1990s. He left the band in 1995 and went on to a hugely successful solo career. That path from group member to solo star has been repeated by many singers since, but few made the transition as dramatically.

The dishwashing machine born from frustration

Josephine Cochrane, an American socialite, is credited with inventing the first practical dishwasher in the 1880s. According to the story, she was tired of her fine china being chipped by servants during washing, so she designed a machine that sprayed water over dishes held in racks. Her invention won a prize at the 1893 World's Columbian Exposition in Chicago.