A question that is about source follower and body effect！

Hi, everybody, I have a question that is about the source follower (common-drain amplifier) and body effect. Why does increasing the output bias level can reduce the percentage of source to bulk voltage due to the signal? Could everybody explain the reason?Thanks.

dude, your English sucks big time.
中文论坛，尽量用中文啦。
简单的说，gmb随着Vsb增大而减小。

感謝你的回答！
我已經知