10 Look carefully at the picture. it shows an electron in the excited state on the left, and the electron returning to its ground state on the right. When the electron return to the ground state it
emits
photon
excited state
ground state
a) blast of cold air
c) proton
b) electrostatic charge
d) photon (light)

You exhale co2 which is produced during cellular respiration.  co2 combines with the water in your blood's plasma to make up one half of the body's most important buffer pair, carbonic acid.  the more physical activity you engage in, the more co2 your body is producing.  you can see this by putting some of the cabbage indicator in a glass and then blowing bubbles into it through a straw.  can you see a change in the color of the indicator?