阅读理解

    Over the last week, a "poisonous kale（甘蓝菜）" theory has been going widespread after an article warned that the vegetable was associated with a variety of medical conditions. It's time to separate fear from fact on the health benefits of kale.

    As a member of the cabbage family, kale is low in calories and rich in nutrients and minerals, especially vitamin A,C and K. Consumed for thousands of years, it's been a health plus for millions of eaters throughout the world.

    However, numerous web articles have reported on some evidence offered by a medicine researcher. The researcher found that thallium（铊）was detected in a few people who were heavy consumers of kale. Thallium is a heavy metal often found in trace amounts（微量）in soil and minerals. His conclusion was that these medical conditions were connected to the impact that trace amounts of thallium detected in some kale samples had on the body.

    I don't think the conclusion is based on a strict scientific basis. It's essential to point out that the original report was in a web magazine, not a scientific journal which is subject to peer review by other scientists. A scientific review includes a careful evaluation of how the findings and conclusions were made. Certain factors are critical before an evidence-based conclusion can be made, such as: how many people were in a study; how well controlled were other factors; how much kale was consumed and for how long; how much thallium was in the kale.

    It is a fact that kale and other vegetables can absorb thallium from the soil. But the ability for a plant to absorb traces of a chemical does not automatically make it harmful to your health. And even finding measurable amounts of thallium in someone's body doesn't imply that the thallium is causing an ill health effect, according to the CDC.

    But we can still learn a lesson from this. Plants grow in soil. Growers must continue to be careful in monitoring the quality of their soil. And what about consumers? Eat your kale—and include lots of other colorful fruits and vegetables. As with all things in nature, variety is key for good health.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

某校实验小组探究“甲状腺激素对蝌蚪生长发育的影响”：取两个相同的玻璃缸，分别贴上标签A、B，实验过程如下表所示，并每天记录蝌蚪生长发育的情况。

阅读课外文章《缺陷的种子》，回答问题。

       15岁那年深秋，父亲让我乘车到县城去购麦种。下了车后，按照父亲指点的位置，我很快就找到了种子交易市场。

       在市场街口，我进了几家种子门市店，门市店里的地上和货柜上摆满了塑料盆盛着的麦种样品，我边和店主说话，边蹲下身子一一观察。那些麦种看起来真 的很好，一粒粒饱满、肥大，捧到手里沉甸甸亮闪闪的，就像一粒一粒的珍珠，几次在店主巧舌如簧的游说下，我差不多就要掏钱购种了，但想起父亲的叮嘱，我还 是最终把捧在手里的麦种依依不舍地又放进了样品盆中。

       父亲说种子公司的国营门市店里有上好的麦种，有省城来的农业教授亲自在那里出售麦种，他再三叮嘱我一定要到种子公司的门市店去，一定要买那个农业教授培育出来的小麦一代杂交新品种。我一路打听着终于找到种子公司的门市店，见到了那个戴着深度近视镜的教授和他培育出来的一代杂交新麦种，不过我失望极了。我的失望不是对教授，而是对教授培育出来的新麦种。那些麦种，个头大小不一，显得十分参差，并且那些麦种也不饱满，一粒一粒瘪瘪的瘦瘦的，还一个个灰头土脸的，几乎没什么光泽，远不如前面那些个体种子店出售的麦种，甚至同我家里收回来的麦粒也不能同日而语。我抓了一把捧在手掌里细细看了足足有三分钟，才怀疑地问站在一旁的教授:“这真的是您培育出来的一代杂交新品种?”教授笑着点点头说:“是的是的。”

       我怀疑地问他:“怎么成色这么差呢?”

       教授解释说:“一代杂交的新品种都这样，种几茬成色就会越来越好了。”我一点也不相信他的解释，母种都这样，还能结出什么样的好麦子来?我断定教授一定是骗人的，只不过是打着教授的幌子想靠出售麦种捞上一笔钱而已，这样的麦粒只配喂鸡，哪里配得上做麦种呢?

       于是，我果断地离开了种子公司的门市店，到街上的个体种子店里买了几十斤颗粒饱满、个个通体金亮的麦种。

       麦种带回家后，我向父亲讲了我的推测，父亲也没说什么，很快就把种子播进地里去了。直到第二年收麦时我和父亲才惊讶地发现，我们家那些颗粒饱满的麦种长出的麦子并不好，麦粒又细又烂不说，产量也很低，而村里几家买教授麦种的人，他们的麦子穗长、粒实，颗粒饱满、金亮，产量高出我家好几倍。

       后来我请教一位搞农业育种的专家，专家一听就笑了，他说，那些一代杂交的种子确实看上去不起眼儿，瘪小，亮色也差，可它们毕竟是一代杂交的呀，它们种一年就变得饱满些，再种一年，就更加饱满了，它们在一年年克服着缺陷，在拼命趋向饱满和完美。而那些看上去饱满、金亮、完美无缺的种子，它已经完美到尽头了，没路再向上走了，所以只有一年年退化，只有一年年向缺陷发展，最后被彻底淘汰掉，永远退出土地和田园。

       原来，在有些时候，完美也是一种缺陷啊，一幅画得太满的没有留白的画，不能给人以想象的空间；一片蓝得没有一丝白云的天空，不能给人以云舒云卷的心灵悠然；一张洁白得没有一点墨迹的纸，不能给人以诗情画意的美蕴；一尊完美无缺的菩萨，不能给人以生活五味的率真……

       完美是一种无法弥补的缺陷，过于完美的人生，恰恰是有缺陷的人生。