If there are 20,000 students in a university, how many would you estimate to have the rh-blood type? (using hardy-weinberg's)

correct answer is a. and d.

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.