Is there a way to stop receiving the 'Just asked' emails only?
At the moment, you cannot unsubscribe from Just asked emails without unsubscribing from every other email that you can receive from Socratic.
This is just a small oversight that the team is trying to fix together with Socratic's email providers. That said, there's no way of telling when the Just asked emails will be included on the list of emails that users can unsubscribe from without affecting other emails.
So, for the time being, you cannot stop receiving Just asked emails only.