The frequency of genes that lead to favorable traits increases because A.
favorable traits always start out as the rare form and become more common
B.
the genes for favorable traits are dominant over those for unfavorable genes
C.
Both B and D
D.
those genes continue on to the next generation when the individuals that contain the genes successfully survive and reproduce

The answeer is both B and D.

life would be meaningless without memes

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.