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Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
Most desert animals will drink water if confronted with it, but many of them never have any opportunity. Yet all living things must have water, or they will expire. The herbivores find it in desert plants. The carnivores slake their thirst with the flesh and blood of living prey. One of the most remarkable adjustments, however, has been made by the tiny kangaroo rat, who not only lives without drinking but subsists on a diet of dry seeds containing about 5% free water. Like other animals, he has the ability to manufacture water in his body by a metabolic conversion of carbohydrates. But he is notable for the parsimony with which he conserves his small supply by every possible means, expending only minuscule amounts in his excreta and through evaporation from his respiratory tract.
Investigation into how the kangaroo rat can live without drinking water has involved various experiments with these small animals. Could kangaroo rats somehow store water in their bodies and slowly utilize these resources in the long periods when no free water is available from dew or rain? The simplest way to settle this question was to determine the total water content in the animals to see if it decreases as they are kept for long periods on a dry diet. If they slowly use up their water, the body should become increasingly dehydrated, and if they begin with a store of water, this should be evident from an initial high water content. Results of such experiments with kangaroo rats on dry diets for more than 7 weeks showed that the rats maintained their body content during the long period of water deprivation. When the kangaroo rats were given free access to water, they did not drink water. They did nibble on small pieces of watermelon, but this did not change appreciably the water intent in their bodies, which remained at 66.3% to 67.2% during this period.
This is very close to the water content of dry-fed animals (66.5%), and the availability of free water, therefore, did not lead to any “storage” that could be meaningful as a water reserve. This makes it reasonable to conclude that physiological storage of water is not a factor in the kangaroo rat’s ability to live on dry food.
1. What is the topic of this passage?
Parrots and macaws have become so rare that special varieties of these birds are fetching up to £9,000 each on the black market in Britain. Macaws from Brazil cost from £1,000 and parrots from Australia can cost £7,500 a pair. The demand for parrots, cockatoos and macaws has led to a (1) ______ increase in thefts from zoos, wildlife parks and pet shops. London and Whipsnade zoos are among the many places from which parrots have been stolen. Some thefts have not been (2) ______ in an effort to prevent further incidents. Parrot rustling, as it is known among bird fanciers, has increased rapidly in Britain since 1976 when imports and exports of exotic birds became (3) ______ controlled. Quarantine controls, coupled with the scarcity of many types of parrots in the wild in Africa, Australia, Indonesia, and South America, have caused a shortage of birds which can be sold legally under (4) _____ This has sent prices to (5) _____ levels. Working at night and equipped with wire-cutters, nets andsubstances to dope the birds, the rustlers are prepared to (6) _____ serious risks to capture the parrots they want. At Birdworld, a specialist zoo, thieves stole two parrots after picking their (7) _____ through an enclosure containing cassowaries, The cassowary is a large flightless bird, related to the emu, which can be extremely aggressive and has been known to kill humans with blows from its powerful legs.
1. _______