Bathymetry is

A. The study of sea water

B. The study of submarine volcanoes

C. The study of plate tectonics

D. The study of ocean contours

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.