远视眼怎么矫正
the fossil record托福综合写作
学会的拼音The fossil record shows that members of the group of dinosaurs known as lambeosaurs had large bony crests on top of their heads.The shape of the crests varied from species to species,but all lambeosaur crests contained extended hollow passages.No one really knows exactly what function the crests rved,but scientists have offered veral theories.
One theory holds that the primary purpo of the crests was to improve the dinosaurs'n of smell.Examination of the fossils has suggested that the crests contained many blood vesls.The no bones of modern animals with a highly developed n of smell have a similar inner structure characterized by a high density of blood vesls.Thus,it is reasonable to conclude that the crests were primarily ud to enhance the n of smell.崔液
消防知识作文
A cond theory maintains that the crests rved to prevent overheating by lowering lambeosaurs'body temperature The addition of a crest had the effect of increasing the surface area of the lambeosaur's body,thereby allowing body heat to escape more rapidly.O
ther warm-climate dinosaurs,stegosaurs for example,also had bony crestlike plates on parts of their body that incread the body surface area lt has long been believed that the bony plates of stegosaurs were adaptations to improve cooling,so it ems likely that the crests of lambeosaurs rved the samepurpo.
一剑万生
A third possibility is that lambeosaurs ud the crests to make sounds,perhaps for communication with other lambeosaurs.lt was definitely possible to make low sounds by forcing air through the crests.This theory is supported by a finding suggesting that lambeosaurs had a good n of hearing:paleontologists recently discovered remains of a lambeosaur that had a highly developed inner ear.A good n of hearing would be necessary for animals communicating by sound.
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