自然界有许多与人方便便是与己方便的例子——在非洲大陆上有一种甜瓜,它的滋味十分迎合土豚的口味,是土豚的最爱。然而,土豚并不是吃了甜瓜之后拍拍屁股就走,它把自己吃了甜瓜后拉下的粪便用泥土埋起来,因为粪便中有未消化的甜瓜籽,土豚就这样“种”下了很多甜瓜。那些种子有土也有肥,来年便结出更多的甜瓜,土豚于是就有了更多的食物。土豚和甜瓜互利互惠,彼此都得以繁衍生息下去。淡水龙虾被捉住放在桶里, There are many examples in nature of convenience and convenience - there is a melon on the African continent, its taste very much catered to the tastes of the Aardvarks and is the favorite of the Aardvarks. However, the aardvarks did not eat the melon after patting the buttocks left, it put their own melon dumped down the soil with mud buried, because there are undigested cantaloupe seeds, "A lot of melons down. Those seeds have soil and fat, and more melons will be produced in the coming year. Therefore, the dolphins will have more food. Aardvark and melon mutual benefit, each other are able to multiply and survive. Freshwater lobster is caught in the bucket,