Knight used natural differences among ponds in the university of florida's ordway-swisher biological station to create a unique field experiment. she selected 8 ponds that were similar in size and depth. four of the ponds contained fish, but the other four contained no fish

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.

if you listed your answers right then i believe your answer is b.