Answer:
• People without any symptoms may be infected and spread the SARS-CoV-2 virus.
• Upon speaking, the virus is released into the air, the louder the more.
• The virus can remain airborne for many hours in classrooms.
• Wearing masks is comparatively cheap and easy to implement and supervise.
• At the same time, wearing masks may have physical side effects.
• Face masks impair face recognition and face identification.
• Face masks impair verbal and non-verbal communication.
• Face masks block emotional signaling between teacher and learner.