Currently, during a poll and and/or after the students have taken a poll, the Polls for Canvas app only shows the percentual fractions of students that submitted answers for each option. There is no way to know the total number of respondents during or after the pool.
This means that there is no way of knowing how many students actually responded to the poll. If you have 100 students and only 10 of them answered, you really do not know if the class is having trouble with the polled concept or not.
Without knowing how many students have already submitted their answers during a poll, it is also impossible lo know when one should close the poll because a representative number of responses have been received.
An example of the Polls For Canvas screen after and while a poll is taken is attached.
Adding the total number of respondents sounds like a necessary and hopefully trivial addition to the app, which would be quite useful for polling answers to multiple-choice questions during synchronous online classes.