请你以Tree’s Function为题，写一篇你对植物功能的了解。

要求：1．条理清晰，符合说明文的结构特点。

      2．语句通顺，句子连贯。

3．字数在100词左右。

1、Trees are very important to US．Do you know why? Let me tell you．

Firstly，trees take in CO₂ from the air and make oxygen．That’s important．People and animals need oxygen to live．If there were no trees on the earth，there would be no lives，either．And they are also useful for the cycle of air．They can also control the climate，make the weather very calm．

    Secondly，many small animals live in trees，they are the homes of many live things，and many animals also feed on their fruit and leaves．In other words，trees can provide food and shelters for these animals．

    Thirdly，the roots of trees can hold the soil，and leaves or the trunks can store plenty water，it can stop water and soil from running away．If we have enough trees，we can stop deserts from moving towards good land．We can also make deserts smaller with the help of trees．

    Next time，when we enjoy the shade of trees in hot summer，recall what I told you．I think you will know more about trees．