词库：word bankvulnerable working together survive cooperate with principles more likely to protect从以上词库中选词填空（直接填单词或短语）。In the animal kingdom, smaller creatures are 1)________________ be eaten by other animals. Therefore, in order to 2)__________, most small animals especially insects live in groups. For example, facing the fierce killer whale, the tiny penguins need to 3)_____________ each other, and the 4)______________ ants have to get united to 5)__________ themselves from being eaten. Interesting enough, teamwork even enable the weak and tiny creatures become the stronger. One good example is that by 6)___________________, the little crabs not only survive but also become strong enough to trim the last feather off the Gull. Clearly, teamwork and team spirits are one of the basic 7)____________ of life in animal world.