A. THEREFORE B. CONSEQUENTLY C. MOREOVER D. HOWEVER IX. RE...

54. A. therefore B. consequently C. moreover D. however IX. Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate thecorrect answer to each of the questions 55 to 64: The daytime quality of light in forests varies with the density of the vegetation, the angle of the Sun, andthe amount of cloud in the sky. Both animals and plants have different appearances in these various lightingconditions. A color or pattern that is relatively indistinct in one kind of light may be quite conspicuous inanother. In the varied and constantly changing light environment of the forest, an animal must be able to sendvisual signals to members of its own species and at the same time avoid being detected by predators. An animalcan hide from predators by choosing the light environment in which its pattern is least visible. This may requiremoving to different parts of the forest at different times of the day or under different weather conditions, or itmay be achieved by changing color according to the changing light conditions. Many species of amphibians(frogs and toads) and reptiles (lizards and snakes) are able to change their color patterns to camouflagethemselves. Some also signal by changing color. The chameleon lizard has the most striking ability to do this.Some chameleon species can change from a rather dull appearance to a full riot of carnival colors in seconds.By this means, they signal their level of aggression or readiness to mate. Other species take into account the changing conditions of light by performing their visual displays onlywhen the light is favorable. A male bird of paradise may put himself in the limelight by displaying hisspectacular plumage in the best stage setting to attract a female. Certain butterflies move into spots of sunlightthat have penetrated to the forest floor and display by opening and closing their beautifully patterned wings inthe bright spotlights. They also compete with each other for the best spot of sunlight. Very little light filters through the canopy of leaves and branches in a rain forest to reach ground level-or close to the ground-and at those levels the yellow-to-green wavelengths predominate. A signal might be mosteasily seen if it is maximally bright. In the green-to-yellow lighting conditions of the lowest levels of the forest,yellow and green would be the brightest colors, but when an animal is signaling, these colors would not be veryvisible if the animal was sitting in an area with a yellowish or greenish background. The best signal depends notonly on its brightness but also on how well it contrasts with the background against which it must be seen. Inthis part of the rain forest, therefore, red and orange are the best colors for signaling, and they are the colorsused in signals by the ground-walking Australian brush turkey. This species, which lives in the rain forests andscrublands of the east coast of Australia, has a brown-to-black plumage with bare, bright-red skin on the headand neck and a neck collar of orange-yellow loosely hanging skin. During courtship and aggressive displays, theturkey enlarges its colored neck collar by inflating sacs in the neck region and then flings about a pendulouspart of the colored signaling apparatus as it utters calls designed to attract or repel. This impressive display isclearly visible in the light spectrum illuminating the forest floor. Less colorful birds and animals that inhabit the rain forest tend to rely on other forms of signaling otherthan the visual, particularly over long distances. The piercing cries of the rhinoceros hornbill characterize theSoutheast Asian rain forest, as do the unmistakable calls of the gibbons. In densely wooded environments,sound is the best means of communication over distance because in comparison with light, it travels with littleimpediment from trees and other vegetation. In forests, visual signals can be seen only at short distances, wherethey are not obstructed by trees. The male riflebird exploits both of these modes of signaling simultaneously inhis courtship display. The sounds made as each wing is opened carry extremely well over distance and advertisehis presence widely. The ritualized visual display communicates in close quarters when a female hasapproached. (Resource: Toefl test strategies by Eli Hinkel, Ph.D)