Orthodontic problems such as crowding and malocclusions are widespread in humans today, but the study of ancient skulls tells us that this was rare before 10,000 years ago. what factors explain this observation?

Today humans suffer more from orthodontic issues compared to ancient humans because of the change of food from hard foods to soft foods. This resulted to smaller faces and smaller jaws together with rounder and shorter cranial vault. This made the bones supporting the teeth reduce in size faster than the teeth resulting to crowding and malocclusions.

Air enters through the nose (and sometimes the mouth), moves through the nasal cavity, the  pharynx, the  larynx, enters the  trachea, moves through the  bronchi  andbronchioles  till the alveoli.