What proportion of a legislative chamber must be present to fulfill the quorum requirement

- Two-thirds.

Explanation:

Quorum is associated with the minimum number of members required to be present at the moment to ensure the conductance of the legislative procedure or business deal.

As per the question, the 'two-thirds section' of a legislative chamber is required to be present in order to accomplish the quorum requirement and conduct the parliamentary procedure. The requirement is primarily designed to ensure minimum attendance in the assembly and avoid the absolute unrepresentative situation.