阅读下面短文，在空白处填入一个适当的词，或填入括号中所给单词的正确形式。

    Malala Yousafzai, 19, is a Pakistani youth activist. She is the ____（young）person in the world ever to be named United Nations（U.N.）Messenger（信使）of Peace. The United Nations is ____ international organization, which is meant to encourage ____（country）to work together on different opinions without the use of war. Yousafzai has ____(glad) accepted the role of working for girls'education. Usually, a messenger ____(stay) in the position（职位）for three years. “If ____ want to see your future bright, you have to start working now and not wait ____ anyone else,” she said at the acceptance meeting in New York. In 2012, Yousafzai was nearly killed by the Taliban because she worked hard ____(get) the same education for young girls in Pakistan. But later her condition improved. ____ a brave girl! Since then Yousafzai ____(become) a symbol for peace and girls' right to receive an education.

人的染色体分布在（    ）

一共有____只蝴蝴蝶。

 Cu+2H₂SO₄(浓)      CuSO₄+SO₂↑+2H₂O

   有人设计了用铜屑制取CuSO₄的两种方案：

 ①Cu $\underset{\Delta }{\overset{浓H_{2}S{O}_4}{\to }}$  CuSO₄  

②Cu $\stackrel{\Delta }{\to }$  CuO $\underset{}{\overset{稀H_{2}S{O}_4}{\to }}$  CuSO₄

从节约原料和保护环境的角度考虑，较好的方案是（  ）