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  3. In an experiment published last month, researchers from the University of Illinois recruited schoolchildren, ages 9 and 10 and a

In an experiment published last month, researchers from the University of Illinois recruited schoolchildren, ages 9 and 10 and a

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问题     In an experiment published last month, researchers from the University of Illinois recruited schoolchildren, ages 9 and 10 and asked them to run on a treadmill, hoping to learn more about how fitness affects the immature human brain.
    The researchers sorted the children, based on their treadmill runs, into highest-, lowest- and median-fit categories. Only the most- and least-fit groups continued in the study (to provide the greatest contrast). Both groups completed a series of cognitive (认知的) challenges. Finally, the children’s brains were scanned, using MRI technology to measure the volume of specific areas.
    Previous studies found that fitter kids generally scored better on such tests. And in this case, too, those children performed better on the tests. But the MRIs provided a clearer picture of how it might work. They showed that fit children had significantly larger basal ganglia, a key part of the brain that aids in maintaining attention and "executive control". Since both groups of children had similar socioeconomic backgrounds, body mass index and other variables, the researchers concluded that being fit had enlarged that portion of their brains.
    The findings arrive at an important time. For budgetary and administrative reasons, school boards are reducing physical education, while on their own, children grow increasingly sluggish (懒散的). Roughly a quarter of children participate in zero physical activity outside of school.
    At the same time, evidence accumulates about the positive impact of even small amounts of aerobic (有氧的) activity. Past studies found that "just 20 minutes of walking" before a test raised children’s scores, even if the children were otherwise unfit or overweight.
    But it’s the neurological (神经的) impact of sustained aerobic fitness in young people that is especially compelling. A years-long Swedish study published last year found that, among more than a million 18-year-old boys who joined the army, better fitness was correlated with higher IQs, even among identical twins. The fittest of them were also more likely to go on to profitable careers than the least fit, rendering them less likely to live in their parents’ basements.
    No correlation was found between muscular strength and IQ scores. There’s no evidence that exercise leads to a higher IQ, but the researchers suspect that aerobic exercise, not strength training, produces specific growth factors and proteins that stimulate the brain.
What does the author try to tell us in this passage?
选项 A、Aerobic exercise can make children smarter.
B、Schools are responsible for children’s fitness.
C、Military training should be taken seriously.
D、Running on a treadmill is the best way of exercise.
答案A
解析 本文首先介绍了伊利诺斯州大学的研究，说明身体更健康的儿童在测试中成绩更好，并说明原因，随后举例说明有氧运动产生的积极影响：考前散步可以提高成绩；身体越健康，智商就越高，由此可知，作者主要是想告诉我们有氧运动能够提高孩子的智商，使孩子更聪明，故答案为[A]。[B]是针对第4段设的干扰项。[C]是针对瑞士的研究设的干扰项。让孩子踩跑步机是伊利诺斯州大学的研究中采用的方式，并不能说明这是最好的锻炼方式，故排除[D]。
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