缺词填空 根据短文内容及首字母提示补全单词
    UNICEF works all over the world.
    UNICEF helps make the world a better place for c____ . We provide clean water, enough food and e____ for poor children in many countries.
    We want children to be healthy so we try to p____  illness. When they're sick, we pay for them to go to a doctor.We also think it's i____  that children go to school. Many children in p____  countries have to work to earn m____  for their families so they can't go to school.
    UNICEF raises money by s____ Christmas cards and organizing other fund-raising a____ .
    There are many w____  you can help UNICEF. You can send a donation or do some v____  work.

回答以下用人工湿地处理生活污水的问题．

（1）应该以水生植物为主，因陆生植物在淹水时，根部细胞会进行____ ，产生____ 等物质，造成对根细胞的伤害；其次尽量选用____ 物种，以保证当地生态系统的安全性，遵循了生态工程建设的____ 原理．

（2）输入此湿地生态系统的能量有____，此系统的建立，下面处理污水，上面又可作为人们休闲、观光的理想场所，体现了生物多样性的____ 价值．

（3）水生植物吸收氮磷的主要方式是____．污水中的重金属可能通过____的途径富集危害人的健康．

小文同学在厨房帮妈妈做饭时观察到了一些现象，用所学物理知识进行了解释，其中解释不正确的是（　　）

How many _______?