Practice Test 28: How Bees Share Directions and the History of the Public Library

A Honeybees live in colonies of tens of thousands, yet a hive has no leader who directs the search for food. Instead, individual scout bees fly out, find flowers that offer good nectar, and return to tell the others. When a successful forager gets back, she performs a dance on the vertical surface of the honeycomb, in the darkness of the hive. This behaviour, known as the waggle dance, was decoded by the Austrian scientist Karl von Frisch, who was awarded a Nobel Prize in 1973 for his work on animal communication.

B The dance follows a figure-of-eight pattern. In the central part of the figure the bee walks in a straight line while shaking her body from side to side, and then she circles back to her starting point to repeat the run. The angle of the straight run, measured against the vertical, shows the direction of the food in relation to the sun. The length of the waggling phase indicates distance: the longer the bee waggles, the farther away the food source is.

C Other bees gather around the dancer and follow her movements, touching her with their antennae. Through this contact they also pick up the scent of the flowers she has visited, which helps them to recognise the right plants once they leave the hive. A single dance is not perfectly accurate and different dancers can vary. However, the colony does not rely on one bee. By combining the information from many dances, the followers arrive at a good estimate of the location. On cloudy days, when the sun cannot be seen, bees can use patterns of polarised light in the sky to find their bearings.

D The waggle dance has been tested with a variety of methods, including a small robotic bee that copied the movements and was followed by real bees. The dance allows a colony to send its foragers to the best patches of flowers and to shift effort as the supply of nectar changes during the season. For this reason it remains one of the most studied examples of how animals can pass precise, symbolic information to one another.

A Today a public library is so familiar that it is easy to forget it was once a radical idea. For most of history, libraries belonged to the powerful. Monasteries, rulers and universities kept collections of hand-copied books that few people could read or even see. The invention of the printing press made books cheaper, but libraries that were open to ordinary people were still rare, and many were run by clubs that charged a membership fee.

B The change came in the nineteenth century, when industrial cities grew quickly and reformers argued that free access to books would educate workers and keep them away from less useful pastimes. In Britain, a law passed in 1850 allowed towns to use money from local taxes to open libraries. Wealthy donors helped to spread the idea. Andrew Carnegie paid for the construction of thousands of library buildings, although he expected local authorities to provide the books, the staff and the running costs.

C In recent years the internet has changed how people use libraries. In many places the number of books borrowed has fallen, yet the buildings are often busier than ever. Visitors come to use computers, to attend classes, to find a quiet place to study or simply to meet others. Many libraries have therefore moved from a focus on collections to a focus on services, offering help with job applications, language lessons and digital skills.

D Not everyone is convinced that libraries should receive public money. Critics ask whether tax revenue would be better spent elsewhere when so much information is available online. Supporters reply that libraries serve people who cannot afford a home internet connection and who need guidance in using it. They also argue that the value of a library cannot be measured by loans alone, and that its future will depend on how well it adapts to what the community needs.