托福听力真题原文+题目+答案：Bones of Dinosaur

托福听力真题原文+题目+答案：Bones of Dinosaur

托福听力真题原文如下：

Have very good ideas of the shape and size of dinosaurs from studying their petrified bones; but we have to hypothesize about their behaviors and life span;cuz that kind of info isn't preserved the way bones and tissues are, or so we thought.

Review: the dinosaur bones were turned into stones through the process of petrifaction.

Petrifaction: when all the original biological material gets replaced with minerals without losing its original states or details.

Can use histology to examine them; histology is the study of biological tissues; to do the study, the petrified bones have to be cut so thin that light can pass through it, then you can examine them under a microscope;Turns out preserved microstructure contains lots of information including keys to behaviors; and long-standing hypothesis about dinosaurs are being proved wrong, and new hypothesis are taking their place Example: one dinosaur had a skull composed of thick bones.

We thought with such a thick bone, the males probably butted heads(when competing for mates); but when looking for evidence of head-butting(like healed cracks or stress fractures);but the analysis clearly showed that there was no sign of such stress to the skull;instead they found a small structure that looked like they may have anchored a crest to the skull(display? recognition?)Another long-standing hypothesis.

The really big dinosaurs took decades to reach full size, after all they hatched from very small eggs; then they did an examine on Apatosaurus bones.

。。。。。余下托福听力真题原文省略！

托福听力题目如下：

1、What is the lecture mainly about

A、New hypotheses about dinosaurs resulting from tissue analysis

B、Factors that allow dinosaur bones to be well preserved

C、The role of histology in determining nutritional needs of dinosaurs

D、The identification of some recently discovered dinosaur bones

2、Why does the professor describe the process of petrifaction

A、To clarify the difference between bone and soft tissue

B、To explain why histology can be used on dinosaur bones

C、To remind students of how long ago dinosaurs lived

D、To describe the origins of some cracks in dinosaur bones

。。。。。余下托福听力真题题目及答案省略！

托福听力真题音频不清楚，请悉知！

5元有偿下载托福听力真题原文+题目+答案：Bones of Dinosaur