Imagine a chemist is in the lab and trying to make some chemical reactions happen. in one reaction she reacts chemicals in an exothermic reaction and there is an increase in entropy. a second chemical reaction she is trying to run is endothermic and there is a decrease in entropy. which of the two reactions is more likely to occur and why?

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?