根据题意及首字母提示填空。

1. Elephants are the most e______ animals in the world.

2. That zoo is s______ for animals to live in.

3. It's important to r______ paper to save the trees.

4. Most people are a______ putting animals in the zoo.

5. The a______ animals should be put in cages.

在某一高度以3m／s的速度沿水平方向抛出一物体，忽略空气阻力，当物体的速度为5m／s时，其竖直方向的分速度为[ ]

A．3m/s

B．4m/s

C．5m/s

D．6m/s