Answer:
Step-by-step explanation:
The result was a decrease in gas volume within the tube, and a related decrease in pressure in the tube. The respirometer with just the glass beads served as a control, allowing changes in volume due to changes in atmospheric pressure and/or temperature.
The purpose of the beads is to ensure that each respirometer is uniform in volume. The vial with glass beads alone will permit detection of any changes in volume due to atmospheric pressure changes or temperature changes.