問題詳情

   Despite their misleading name, cuttlefish are not fish but belong to the class Cephalopoda, which also includes squids and octopods.They generally range in size from 15 to 25 cm, with the largest species reaching 50 cm and over 10.5 kg. Their preferred diet is small mollusks, crabs, shrimp, and fish, and their predators include dolphins, sharks, seals, and seabirds. The average life expectancy of a cuttlefish is about one to two years. As for their habitats, all cuttlefish inhabit tropical/temperate ocean waters. They are mostly shallow-water animals, although they are known to go to depths of about 500 m. They have an unusual biogeographic pattern: totally absent from the Americas, but present along the coasts of Asia, Western Europe, and the Mediterranean, as well as all coasts of Africa and Australia.   Cuttlefish are one of the most fascinating marine animals. These highly evolved creatures have existed since the Cambrian Period,600 million years ago. An easy examination of cuttlefish can reveal many of the characteristics that have contributed to this evolutionary success story. First, cuttlefish, like other cephalopods, have sophisticated eyes. Cuttlefish’s large pupils are a smoothly curving W-shape.Although cuttlefish cannot see color, they can perceive the polarization of light, which enhances their perception of contrast. Unlike the vertebrate eye, there is no blind spot, because the optic nerve is positioned behind the retina.   Another apparent feature of cuttlefish anatomy is the arrangement of its short, stubby arms, eight of which are arranged in pairs in a radial pattern surrounding the mouth. These eight appendages, furnished with suckers, are used primarily for capturing prey and pulling it toward the beak. They are dramatically shorter and stubbier than those of most the cuttlefish’s other cephalopod cousins.   The next distinctive feature of cuttlefish is the undulating ribbon-like fins that run the length of the cuttlefish’s body. These serve to propel the animal through the water with astounding agility. This mobility may have made it unnecessary for cuttlefish to possess the long powerful arms characteristic of the octopus and squid.   There are times, however, when even this agility isn’t enough. When an aggressive predator makes life difficult, cuttlefish can resort to other defensive measures, such as a smoke screen and camouflage. Cuttlefish have ink, like squid and octopus species, stored inside an ink sac. By expelling a jet of water mixed with the black ink, cuttlefish can move away at great speed while simultaneously concealing its departure behind a dark cloud in the water. Camouflage is another smart strategy that cuttlefish will employ. Sometimes referred to as the “chameleons of the sea,” cuttlefish are able to rapidly change the color of their skin and create chromatically complex patterns to match their surroundings even in total darkness. In this way, they can confuse, frighten or evade potential enemies.   Recent studies indicate cuttlefish, like its relative octopuses, are among the most intelligent invertebrates. Cuttlefish also have one of the largest brain-to-body size ratios of all invertebrates. It has even been suggested by scientists that these intriguing creatures can generate rapid, sequential changes of color to communicate with each other. If this turns out to be true, it is likely the only instance of such color-based language in the animal kingdom.
46. What is the main idea of this passage?
(A) There are physically differences between cuttlefish, squid, and octopuses.
(B) Cuttlefish communicate with others of its species in some intriguing ways.[!--empirenews.page--]
(C) Several distinctive features contribute to the survival of cuttlefish.
(D) Cuttlefish’s eight arms have been developed mainly for the purpose of intimidating prey.

參考答案

答案：C
難度：適中0.666667
統計：A(3),B(2),C(16),D(1),E(0)

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