ND Chapter 44-04-17. 14.
"Quorum" means one-half or more of the members of the governing body, or any smaller number if sufficient for a governing body to transact business on behalf of the public entity.
NDSU Bylaws: Part VII, Section 11
In order to conduct business, a quorum of at least sixty percent of the total voting membership of the Senate shall be present. (43 members)
RROO, 10th edition, § 40.
In the absence of a quorum, any business transacted... is null and void. Exceptions to the rule are adjourn, recess, and measures to obtain a quorum.
The prohibition against transacting business in the absence of a quorum cannot be waived even by unanimous consent.
Where an important opportunity would be lost unless acted upon immediately, the members present can, at their own risk, act in the emergency with the hope that their action will be ratified by a later meeting at which a quorum is present.
Given the clear prohibition on business done in the absence of a quorum and the democratic principle of majority rule and participation, it is the duty of the chair and members to be vigilant in ensuring a quorum exists or drawing the Senate's attention to when it does not exist.
However, if a quorum is lost and the Senate, through an honest oversight, does not recognize this fact, then some prior actions can be legitimate. It is only with clear and convincing proof that a quorum did not exist during the action that the chair can affect prior action, including voiding it.
There is no rule stating that the Senate may continue doing business if no one asks for a quorum.