In the periodic table, the period number indicates a. the number of valence electrons for elements in that period. b. the reactivity levels for elements in that period. c. the number of the outermost energy level for elements in that period. d. the number of dots shown on the lewis dot diagrams for elements in that period. mark for review (will be highlighted on the review page)

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?