A. THEREFORE B. CONSEQUENTLY C. MOREOVER D. HOWEVER A. THEREFO...

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 indicatethe correct 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 theSun, and the amount of cloud in the sky. Both animals and plants have different appearances in thesevarious lighting conditions. A color or pattern that is relatively indistinct in one kind of light may be quiteconspicuous in another. In the varied and constantly changing light environment of the forest, an animal must be able tosend visual signals to members of its own species and at the same time avoid being detected by predators.An animal can hide from predators by choosing the light environment in which its pattern is least visible.This may require moving to different parts of the forest at different times of the day or under differentweather conditions, or it may 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 theircolor patterns to camouflage themselves. Some also signal by changing color. The chameleon lizard hasthe most striking ability to do this. Some chameleon species can change from a rather dull appearance to afull riot of carnival colors in seconds. By this means, they signal their level of aggression or readiness tomate. Other species take into account the changing conditions of light by performing their visual displaysonly when the light is favorable. A male bird of paradise may put himself in the limelight by displayinghis spectacular plumage in the best stage setting to attract a female. Certain butterflies move into spots ofsunlight that have penetrated to the forest floor and display by opening and closing their beautifullypatterned wings in the 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 groundlevel-or close to the ground-and at those levels the yellow-to-green wavelengths predominate. A signalmight be most easily seen if it is maximally bright. In the green-to-yellow lighting conditions of the lowestlevels of the forest, yellow and green would be the brightest colors, but when an animal is signaling, thesecolors would not be very visible if the animal was sitting in an area with a yellowish or greenishbackground. The best signal depends not only on its brightness but also on how well it contrasts with thebackground against which it must be seen. In this part of the rain forest, therefore, red and orange are thebest colors for signaling, and they are the colors used in signals by the ground-walking Australian brushturkey. This species, which lives in the rain forests and scrublands of the east coast of Australia, has abrown-to-black plumage with bare, bright-red skin on the head and neck and a neck collar of orange-yellow loosely hanging skin. During courtship and aggressive displays, the turkey enlarges its coloredneck collar by inflating sacs in the neck region and then flings about a pendulous part of the coloredsignaling apparatus as it utters calls designed to attract or repel. This impressive display is clearly visiblein the light spectrum illuminating the forest floor. Less colorful birds and animals that inhabit the rain forest tend to rely on other forms of signalingother than the visual, particularly over long distances. The piercing cries of the rhinoceros hornbillcharacterize the Southeast Asian rain forest, as do the unmistakable calls of the gibbons. In denselywooded environments, sound is the best means of communication over distance because in comparisonwith light, it travels with little impediment from trees and other vegetation. In forests, visual signals canbe seen only at short distances, where they are not obstructed by trees. The male riflebird exploits both ofthese modes of signaling simultaneously in his courtship display. The sounds made as each wing isopened carry extremely well over distance and advertise his presence widely. The ritualized visual displaycommunicates in close quarters when a female has approached. (Resource: Toefl test strategies by Eli Hinkel, Ph.D)