When you breathe in, the diaphragm moves downward toward the abdomen, and the rib muscles pull the ribs upward and outward. This makes the chest cavity bigger and pulls air through the nose or mouth into the lungs.
The respiratory system is the network of organs and tissues that help you breathe. It includes your airways, lungs, and blood vessels. The muscles that power your lungs are also part of the respiratory system. These parts work together to move oxygen throughout the body and clean out waste gases like carbon dioxide.
To find the density of an object, divide the mass by the volume. To find the density of the object in your problem, use a calculator to divide 60.0 by 400.0
