Can the legislative body of the autonomous State exclude the Legislature of Assam from making laws regarding certain matters?
From the context provided, it can be understood that the legislative body of the autonomous State created under this law has the power to make laws for certain specified tribal areas in Assam. The question asks if the autonomous State's legislative body can exclude the Legislature of Assam from making laws regarding certain matters.

According to the context, it is not explicitly mentioned whether the autonomous State's legislative body can exclude the Legislature of Assam from making laws regarding certain matters or not. However, based on clause (1) of the given text, which states "Parliament may, by law, form within the State of Assam an autonomous State comprising (whether wholly or in part) all or any of the tribal areas specified in 7[Part I] of the table appended to paragraph 20 of the Sixth Schedule and create therefor— (a) a body, whether elected or partly nominated and partly elected, to function as a Legislature for the autonomous State," it could be inferred that the legislative body of the autonomous State created under this law might have some degree of autonomy and authority over its specific tribal areas.

However, without more explicit information from the context, it is difficult to definitively determine whether the autonomous State's legislative body can exclude the Legislature of Assam from making laws regarding certain matters.