The cultural makeup of the u. s. population has changed over the past few years because of immigration and other factors. such long-term changes in the genetic and cultural makeup of a population are part of

the answer to your question is:

c. complementary base-pairing

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.