Do you know the boy in the picture? He is Yi Yangqianxi. His English name is Jackson. Yi is 15 years old. He is a student in a school in Beijing. And he is also a boy in the group (组合) TFBOYS.

    TFBOYS has three boys — Wang Yuan, Wang Junkai and Yi Yangqianxi. All of them are tall and have good looks. They are good at dancing and singing.

    Wang Yuan and Wang Junkai are Yi's friends. And Yi has another (另一个) friend. He is a toy bear. He lives in Yi's schoolbag. Yi goes to school with him every day. He talks and plays with him. “He can't talk, but he can listen to me. He is very nice. I like him very much,” Yi says. “I don't want to be away from him.”

影响生物生活的非生物因素有____、____、____、____、____等．

在公园的草坪上主人和小狗正在玩飞碟游戏，如下图所示．飞碟以v₀=10m/s沿水平方向抛出，假设飞碟抛出后做匀速直线运动，在空中飞行的时间为t₀=5s；小狗在1s内匀加速到v=10m/s，然后做匀速直线运动．当抛出飞碟的同时小狗应在离主人多远的地方向飞碟跑去，才能在飞碟刚要落地时恰好接住？（小狗与飞碟运动同向共线）

人们经常在草坪上行走，会造成土壤板结，从而影响草的生长．土壤板结影响植物生长的主要原因是（　　）