問題詳情

第三篇：Australia’s cuddly koala rarely drinks water and doesn't have any sweat glands, long leaving scientists to wonderhow it cools off in a heatwave.On Wednesday, zoologists announced they had uncovered the iconic mammal’s secret—hugging trees, whosetrunks can be several degrees cooler than the surroundings.Koalas have high mortality rates in heatwaves. Unable to sweat, they use panting as a way of evaporativecooling, but in the wild, they rarely drink and when they need to, water is often scarce. As tree-dwellers, koalas don'tgenerally seek out cool, shadowy ground surfaces like many other animals.Keen to unlock the marsupials' secret, a team of zoologists observed 37 koalas in the wild during winter andsummer seasons in southeastern Australia in 2009 and 2010-11. On hotter days, they found, the animals were morefrequently positioned with all their limbs outstretched so they appeared to be hugging the tree trunk or lower branches.The warmer it got, the lower the marsupials were found in the trees, and more often in trees other than eucalyptus,their food source. This could be explained by the eucalyptus being only about 1.46-1.87 degrees Celsius cooler thanair temperature, compared to about 5.0 C for the acacia.Based on their observations of tree temperature and koala behavior, the team concluded the animals lose“substantial” body heat to tree trunks in hot weather. Water savings from this behavior could be critical for thesurvival of this species during heatwaves when water availability is limited.
11. Where is this passage most likely taken from?
(A) A guide to forestry.
(B) A biology journal.
(C) A health magazine.
(D) A geology textbook.

參考答案

答案：B
難度：適中0.629921
統計：A(46),B(160),C(7),D(28),E(0)

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