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共用题干 Dangers Await Babies with Altitude

昕玥2019-12-17  47
问题 共用题干Dangers Await Babies with Altitude
Women who live in the world's highest communities tend to give birth to under-weight ha-bies,a new study suggests.These babies may grow into adults with a high risk of heart disease and strokes.
Research has hinted that newborns in mountain communities are lighter than average.But it wasn't clear whether this is due to reduced oxygen levels at high altitude or because their mothers are under-nourished—many people who live at high altitudes are relatively poor compared with those living lower down.
To find out more,Dino Giussani and his team at Cambridge University studied the records of
400 births in Bolivia during 1976 and 1998.The babies were born in both rich and poor areas of two cities:La Paz and Santa Cruz. La Paz is the highest city in the world,at 3 .65 kilometers a-bove sea level,while Santa Cruz is much lower,at 0.44 kilometers.
Sure enough,Giussani found that the average birthweight of babies in La Paz was significant-ly lower than in Santa Cruz.This was true in both high and low-income families.Even babies born to poor families in Santa Cruz were heavier on average than babies born to wealthy families in lofty La Paz.“We were very surprised by this result,”says Giussani.
The results suggest that babies born at high altitude are deprived of oxygen before birth.
“This may trigger the release or suppression of hormones that regulate growth of the unborn child,”says Giussani.
His team also found that high-altitude babies tended to have relatively larger heads compared with their bodies. This is probably because a fetus starved of oxygen will send oxygenated blood to the brain in preference to rest of the body.
Giussani wants to find out if such babies have a higher risk of disease in later life.People  born in La Paz might be prone to heart trouble in adulthood,for example.Low birth weight is a risk factor for coronary（冠状的）heart disease. And newborns with a high ratio of head size to body weight are often predisposed to high blood pressure and strokes in later life.
选项 What does the new study discover?A: Babies born to wealthy families are heaver.B:Women living at high altitude trnd to give birth to underweight babies.C: Newborns in cities are lighter than average.D: Low-altitude babies have a high risk of heart disease in later life.
答案B
解析根据文章首句以及后文的研究结果可知住在世界高海拔地区的女人通常生下体重不足的婴儿。因此B项正确。 由文章第四段“Sure enough, Giussani found that the average birthweight of babies in La Paz was significantly lower than in Santa Cruz.”可知，吉萨尼和他的团队确信，拉帕兹的新生儿的平均出生体重明显低于散塔克鲁兹的新生儿。因此本题选A。 根据吉萨尼说的话可知，研究结果令他们吃惊。也就是，研究结果是意料之外的。 根据第五段“The results suggest that babies born at high altitude are deprived of oxygen before birth.”可知，那些体重不足的婴儿在出生前就缺氧了。因此D项正确。 由文章倒数第二段可知，团队还发现高海拔的婴儿通常有相对身体来说较大的头部。最后一段最后一句指出，头部相对身体较大的新生儿在今后的生活中通常更容易得高血压和中风。由此知道，高海拔的婴儿在晚年更容易得高血压。故本题选A。
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