53 至 56 題為題組
Many marine animals, including penguins and marine iguanas, have evolved ways to get rid of excess
salt by using special salt-expelling glands around their tongue. However, the sea snake’s salt glands cannot
handle the massive amounts of salt that would enter their bodies if they actually drank seawater. This poses
a serious problem when it comes to getting enough water to drink. If seawater is not an option, how does
this animal survive in the ocean?
An international team of researchers focused on a population of yellow-bellied sea snakes living near
Costa Rica, where rain often does not fall for up to seven months out of the year. Because yellow-bellied
sea snakes usually spend all of their time far from land, rain is the animals’ only source of fresh water.
When it rains, a thin layer of fresh water forms on top of the ocean, providing the snakes with a fleeting
opportunity to lap up that precious resource. But during the dry season when there is no rain, snakes
presumably have nothing to drink. Thus, the team became interested in testing whether sea snakes became
dehydrated at sea.
第 7 頁 105年學測
共 7 頁 英文考科
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The researchers collected more than 500 yellow-bellied sea snakes and weighed them. They found that
during the dry season about half of the snakes accepted fresh water offered to them, while nearly none did
during the wet season. A snake’s likelihood to drink also correlated with its body condition, with more
withered snakes being more likely to drink, and to drink more. Finally, as predicted, snakes captured during
the dry season contained significantly less body water than those scooped up in the rainy season. Thus, it
seems the snake is able to endure certain degrees of dehydration in between rains. Scientists believe that
dehydration at sea may explain the declining populations of sea snakes in some parts of the world. 【題組】56. What can be inferred from the study?
(A) Sea snakes can easily survive long years of drought.
(B) Evolution will very likely enable sea snakes to drink seawater.
(C) Sea snakes will be the last creature affected by global warming.
(D) The sea snakes’ population distribution is closely related to rainfall
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