When you watch TV programs about wild animals,it is surprising to see how an antelope (羚羊) can run a
题目
When you watch TV programs about wild animals,it is surprising to see how an antelope (羚羊) can run away from a strong lion.In the wilderness,everyone has his own way to protect himself.Even plants have their own ways to fight off enemies.
Over millions of years,plants have developed their own defense system (防卫系统).Chemicals are fantastically used by plants to survive (幸存).By making their leaves,flowers,roots and fruits poisonous (有毒的) to enemies,plants can fight back.
One such plant is the Golden Wattle tree.The British scientist David Cameron has found when an animal eats the tree’s leaves,the amount (数 量) of poison increases in the other leaves.“It’s like the injured leaves telephoning the others to fight together against the enemy,” he said.
The tree also sends defense messages to neighboring plants by giving out a special smell.Golden Wattle trees in the nearby 45 meters will get the message and produce more poison within 10 minutes.Now,if an enemy eats too many of the
答案
当你看关于野生动物的电视节目,令人吃惊的是看到一只羚羊可以逃离的雄师.在旷野中,每个人都有他自己的方式来保护自己.植物也有他们自己的方式来击退敌人.
数百万年来,植物都开发了自己的防御系统.化学品是非常使用的植物生存.通过他们的叶子,花,根和果实有毒植物可以反击敌人.
这种植物是金合欢树.英国科学家戴维卡梅伦发现,当动物吃树上的叶子,在其他叶毒量增加.“这就像受伤的叶子给别人打起来反对共同的敌人,
举一反三
已知函数f(x)=x,g(x)=alnx,a∈R.若曲线y=f(x)与曲线y=g(x)相交,且在交点处有相同的切线,求a的值和该切线方程.
我想写一篇关于奥巴马的演讲的文章,写哪一篇好呢?为什么好
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