植物受伤时，会释放出系统素(一种由18种氨基酸组成的多肽)与害虫和病原微生物的受体结合，活化蛋白酶抑制基因，抑制蛋白酶活性，限制植物蛋白的降解，从而阻止害虫取食和病原菌繁殖。下列关于系统素的描述，正确的是(　　)

    探春，贾政与赵姨娘生的女儿。她不认生身之母为母女关系，曾说：“我只管认得老爷太太两个人，别人我一概不管，就是兄弟姊妹跟前（暗示对同母弟弟贾环），谁和我好，我就和谁好，什么偏的、庶的，我也不知道。”

    她独具胸怀，又与大观园众姊妹不同。“我但凡是个男人，可走得出去，我早走了，立出一番事业来，那时自有一番道理。”探春这番话可见她非同一般的志向。

    她勇建海棠社，在建社宣言中写道：“孰谓雄才莲社，独许须眉；不教雅会东山，让余脂粉耶？”众姐妹及宝玉都听她的号令，入社吟诗谈文。

    凤姐患病时，她和李纨、宝钗暂摄家政，对大观园进行了一番改革，办了三件大事。第一件，她提出来取消了宝玉、贾环、贾兰三人上学的点心、纸笔月银，该项是以上学为名的开支，实际上津贴了袭人、李纨、赵姨娘。第二件，把各位姑娘每月头油粉钱二两银子也取消了，因各位姑娘，每月各有其月费银子，此项开支是重复。第三件，探春觉得家仆中赖大家的花园管理有办法，联想到大观园中每年所产稻米、竹笋、莲藕、花、果、鱼虾等，年产可值四百两银子，全都糟踢了。因而提出委派园中服役的婆子、媳妇分别承包起来，除给姑娘的头油、脂粉、花瓶、鸟食等外，各自享有剩下的盈余。探春的改革，部分地纠正了贾府的弊端。

    探春最值得称道的，是她在“抄检大观园”过程中的表现。一花独秀，主子中能够反抗的只有探春。她不愧庶出，她没有白白付出代价，她已经学会了在不利情况下捍卫自己的尊严。她言语尖刻，说得又狠又准。她读书知理，能一眼判定此次搜检的极不正常的性质与严重后果。她敢于斗争，一个耳光的清脆响声永垂天地。《红楼梦》中整日男男女女吃吃喝喝，哭哭笑笑，本来就少阳刚之气，“抄检大观园”读起来更是令人憋气，幸亏有探春这个耳光，金声玉振，为抄检的受害者也为读者出了一口恶气。

有的人独自学习效率高，有的人与其他同学一起学习效果好；有的人晚上学习效率高，而有的人早晨学习状态好。这说明（    ）

    A research has shown that nearly 90 percent of traffic accidents are caused by human errors. So our aim is a fully autonomous car that gets rid of the cause of most accidents: the driver. Researcher Hodgson points out, “For safety, the faster you can remove humans, the better, even if there are unfortunately a few accidents from new causes. It s a question of balancing the number injured or killed by autonomous vehicles with the people whose lives are potentially saved.”

    It’s an idea that Elon Musk, chief executive of electric car company Tesla Motors, has long believed. His company are determined to be the first to deliver a fully autonomous vehicle to consumers. Last year, Musk announced that Tesla’s 2017 goal was “to do an example drive of full autonomy all the way from LA to New York…and have the car park itself.”

    However, even Tesla admits that there are problems to overcome—the software needs further validation and the appropriate regulatory approval needs to be in place. Indeed, recent crashes of Tesla vehicles and Google cars confirm that the software isn’t ready yet.

    The UK government appears committed to encouraging the development of autonomous vehicles. It’s supporting four city trials, publishing the Modem Transport Bill to reduce red tape around their introduction and adapting the legal system to take into account problems such as insurance liability when a human isn’t in control of a vehicle.

    The insurance industry is similarly eager to help increase autonomy in cars. As the Association of British Insurers (ABI) points out, “More than 90 per cent of road accidents are caused by human error.” This costs motor insurers a shocking £20m per day in claims.