How does our ribs and diaphragm enable breathing in and out to occur?

When we breath in muscles move our ribs move up and out and our diaphragm contracts. This increases the volume in our chest cavity and decreases the pressure. This means air is pulled in and our lungs fill. When we breath out the diaphragm relaxes and our ribs move inwards. This decreases the volume of our chest cavity and increases the pressure, forcing the air out of our lungs.