it is fixed by it is fixed by law,agreement,or other means.

it is fixed by it is fixed by law,agreement,or other means.
it is fixed by
it is fixed by law,agreement,or other means.

it is fixed by it is fixed by law,agreement,or other means.
这已经由法律、协议和其他方式确定下来

其已经由法律、协议或其他方式确定。

它是由法律规定

这是法律上已经界定（确定）了的！