Which two scenarios illustrate the relationship between pressure and volume as described by Boyle’s law? 1. The pressure in a closed bottle decreases when the bottle is squeezed.
2. The volume of an underwater bubble increases as it rises and the pressure decreases.
3. The pressure increases in an inflated plastic bag when the bag is stepped on.
4. When air is blown into a balloon, the pressure and volume both increase.

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?