如图A﹣﹣E示意人体的不同结构层次，请据图填空．

（1）整个人体都是由A发育而来的，A是____ ．

（2）A通过____形成B，在此过程中，____ 复制后形成形态、数量完全相同的两等份，分别进入两个新细胞．

（3）B通过____形成C，在此过程中，细胞的形态、结构和功能产生了差异．

（4）D是____ ．能够共同完成一种或几种生理功能的多个器官按照一定的次序组合在一起，就构成了____ ．

阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。

For many years, volunteers, both young and old, have been helping the poor and elderly people of this area. They work long hours building wheelchair paths, fixing leaky(有漏洞的) roofs and repairing the homes of those____ need help. Their only payment is the happy smiles and grateful hearts of the people whom____have helped.

I will always remember one man in particular____he has a real enthusiasm for voluntary work. He seemed to have inspired all the people in his group with his____(cheer) spirit. Every day when I asked him____he was doing, he would reply, “I'm doing good!”____the end of the month as he was preparing to leave, I looked at all the homes he ____(fix) and had to agree that he was indeed doing____good job!

A nice house, a successful career, and a lot of money might be nice to have, but____(compare) with fixing others' home and helping those who are in need, their____(significant) is not so great.

用频率为ν的单色光照射某种金属时，逸出光电子的最大动能为E_K，已知普朗克常量为h，则该金属的逸出功为____；若改用频率为2ν的单色光照射此种金属时，则逸出光电子的最大动能为____．