树生长在一定的环境里，它的生长需要阳光、空气、____和适宜的温度。

听短文，写出所缺部分。

    Hi! My name is Linda! I'm a middle school student. It was____lastSunday．After breakfast, my grandparents went for a walk in the park with their dog．They liked the____air there．My father____with his friend．My mother had to____．What about my brother? He read a book about____in his room．I practiced the piano in the living room．

下列选项，不会造成食物链缩短的是（　　）