Which of the following motions is not able to be amended?

The motion known as "Previous Question" is a specific procedural motion in parliamentary procedure that serves to end debate on a main motion or an amendment and brings the assembly to a direct vote. One of the defining characteristics of this motion is that it cannot be amended. This is because its sole purpose is to facilitate the process of concluding discussion and moving to a vote, thus maintaining efficiency in the meeting's proceedings.

Since "Previous Question" is solely focused on the urgency and procedure of voting rather than on the content of the motions being debated, allowing it to be amended would undermine its fundamental purpose. In contrast, motions such as "Amend" and "Main Motion" can definitely be amended, as they are intended to modify or discuss the specifics of business being conducted, inviting input and changes. Additionally, the "Commit or Refer" motion, which directs a matter to a committee for further study, can also be amended to modify the nature of the commitment. Thus, the inability to amend "Previous Question" distinguishes it clearly from the other motions listed.