The best reason I can think of for why we believe that air is a mixture is that freezing air slowly yields different liquids at different temperatures. Liquid nitrogen has a different boiling point than liquid oxygen. They also freeze at different temperatures.
An inguinal hernia is a protrusion of abdominal-cavity contents through the inguinal canal. Symptoms are present in about 66% of affected people. This may include pain or discomfort especially with coughing, exercise, or bowel movements. Often it gets worse throughout the day and improves when lying down.
An incarcerated inguinal hernia is a hernia that becomes stuck in the groin or scrotum and cannot be massaged back into the abdomen. An incarcerated hernia is caused by swelling and can lead to a strangulated hernia, in which the blood supply to the incarcerated small intestine is jeopardized.