根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
What do you, the trees, and a bird have in common? 71 All living things must have water to survive, whether they get it from a water fountain, a rain cloud, or a little bottle attached to the side of a bird cage．
72 Water makes up more than half of your body weight and a person can’t survive for more than a few days without it．Why? Your body has lots of important jobs and it needs water to do many of them．For instance, your blood, which contains a lot of water, carries oxygen to all the cells of your body．Without oxygen, those tiny cells would die and your body would stop working．
