Carbon dioxide is a waste product of your cell's metabolism. You exhale carbon dioxide from your lungs. Carbon dioxide
moves from your cells to your lungs through your blood, which
it enters by diffusion. Which statement best describes how
carbon dioxide enters your blood?
Carbon dioxide moves from a higher concentration
a in your cells to the lower concentration in your
bloodstream.
Carbon dioxide moves from a lower concentration
b in your cells to the higher concentration in your
bloodstream.
Carbon dioxide moves from a higher concentration
C in your lungs to the lower concentration in your
bloodstream.
Carbon dioxide moves from a lower concentration
d in your lungs to the higher concentration in your
bloodstream.