下列关于细菌、真菌与人类关系的叙述，错误的是（    ）

    Bobby was six years old, and he went to school. There were nineteen other little boys and girls in his class. They often went to parties together.

    When one of the children had a birthday, he or she invited all the other children to come to a party. And at Christmas all the mothers had parties for all the children.

    Bobby like parties very much .He liked the games they played there ---but he liked the nice food more .His favorite food was cakes.

    Before a party, Bobby's mother always asked him not to eat too many cakes, and Bobby always answered ,”I won't ,Mom .”But he always ate a lot and sometimes he got ill .Christmas came again, and again there were a lot of parties. Bobby went to all of them. The last one was on January 6^th.

    One evening before this party, Bobby's mother called the lady who had the party, Bobby always eats too many cakes at parties. Don't worry, answered the lady “At the party, a child can only have three cakes ---and the cakes are small”

    “Oh, good!” Bobby's mother answered happily. On January 6^th, she took Bobby to the party. When it was time to eat ,Bobby took four cakes and began to eat them .”You can only have three cakes ,Bobby！＂said the lady .She asked the boy to put the fourth one back on the plate.

    “I can't,” answered Bobby .I ate that one first”

根据短文 ，回答问题。

若尔盖草原是我国最大的泥炭沼泽分布区。泥炭是一种经过几千年所形成的天然沼泽地产物，又称草炭或泥煤，可以为工农业生产提供原材料。二十世纪六七十年代，若尔盖沼泽萎缩，土地板结硬化，风沙蔓延。下图示意若尔盖草原位置。