卵生动物黄腹三足蛇直接产仔
One creature on this planet is changing so greatly that researchers believe they’re watching evolution in action even though they have no idea why.
This strange-looking creature is called a yellow-bellied three-toed skink(黄腹三趾蜥蜴), a species of reptile native to eastern Australia. For most of its known history on Planet Earth, this type of skink has given birth by laying eggs, but recently scientists have noticed something unusual.
Yellow-bellied skinks in the warm coastal lowlands are continuing to lay eggs, but the same species in the colder mountainous regions are starting to give birth to live young. This means that this type of skink is evolving to a new way of birth right before our very eyes. It is the first time in history that scientists have caught a reptile changing from one behavior to the other.
Baby mammals get nutrients from the placenta(胎盘), and babies incubated inside eggs get their nutrients from the yolk and shell. Without either one of these protective casings(外壳), how live skink babies are living is not known now.
1.This kind of yellow-bellied skink lives in _______.
A northern Australia
B southern Australia
C eastern Australia
D western Australia
解析：选C。细节理解题。根据第二段第一句This strange-looking creature is called a yellow-bellied three-toed skink, a species of reptile native to eastern Australia.可知这种黄腹蜥蜴生活在澳大利亚东部，故选C。
2.This kind of skink gives birth by__________ in its known history.
A laying eggs
B growing branches
C giving birth to live young
D copying itself and cutting into halves
解析：选A。A 细节理解题。根据第二段第二句For most of its known history on Planet Earth, this type of skink has given birth by laying eggs, but recently scientists have noticed something unusual.可知历史上这种黄腹蜥蜴是以产卵的方式生殖繁育的，故选A。
3.The underlined word “evolving” means ______ in Chinese.
A 变化
B 进化
C 退化
D 老化
解析：选B。词义猜测题。根据第三段第二句This means that this type of skink is evolving to a new way of birth right before our very eyes.可知这种动物在我们眼前变化形成了新的生育方式，根据常理可知应该是进化，故选B。
4.Where did the baby skink get nutrients from?
A The placenta.
B The yolk.
C The shell.
D We don’t know.
解析：选D。细节理解题。根据第四段第二句Without either one of these protective casings, how live skink babies are surviving is not known now.可知这种胎生黄腹蜥蜴的幼崽在母体内从哪里获取营养并不清楚，故选D。
5.Where can you read this passage?
A In a travel guide.
B In a science magazine.
C In a health book.
D In a political newspaper.
解析：选B。B 文章标题题。文章主要讲述了澳大利亚东部的黄腹蜥蜴进化为胎生可知这应该属于科学类文章，应该出现在科学类杂志上，故选B。