Gayle was excited to wake up to a few inches of snow. It was just enough to build a snowman. She and her sisters quickly put on their mitts and ran outside to begin
building their snowman. Later that morning the snowman began to melt, What
most likely caused the snowman to melt?
A. electrical energy
B sound energy
C. mechanical energy
heat energy

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?