Mouth to mouth or nose should normally be used for artificial respiration because they are what?

Mouth to mouth or nose artificial respiration is performed when breathing is impaired to provide enough oxygen to sustain the person's life until further medical assistance arrives. It does not involve any physical apparatus. The main reason why direct methods like mouth to mouth or nose are preferred over any assistive devices is because of their simplicity and universal accessibility. These methods do not require any specialised equipment or training and hence, allows bystanders or untrained individuals to provide immediate aid in emergency situations, thus increasing the chances of survival.