Question

What are some likely reasons the classroom doorknob is among the least infected areas in a classroom

Answer 1

that the doorknob isn't used that recently by students, since they don't really use that to study.

Answer 2

Brass doorknobs exhibit an effect known as The Oligodynamic Effect.

This property of a metal means that it will react with the amine groups of enzymes or protein found in bacteria, and kill them.

Most heavy metals exhibit this antiseptic ability.