Science Assessment

A group of scientists was interested in finding out how the amount of energy needed to do yoga exercises compared to other forms of exercise. During a typical yoga session, a person moves through a series of poses like the ones shown below.

The scientist recruited 20 people to participate in the study. They first had each person rest for 30 minutes by sitting still in a chair. Then each person moved through a series of standing and sitting yoga poses for 56 minutes. Finally, each person walked on a treadmill at two different speeds (2 miles per hour and 3 miles per hour) for 10 minutes at each speed.

During each part of the study, the scientists determined how much oxygen each person used by calculating the difference between the amount of oxygen inhaled and the amount of oxygen exhaled. The table below presents the average amount of oxygen used during each activity.

Another scientist wants to measure the amount of carbon dioxide exhaled instead of the amount of oxygen used. What patterns would this scientist find and why?

1. The scientist would find that the amount of carbon dioxide exhaled increases with increased amount of activity because carbon dioxide is formed during the chemical reaction that supplies the energy needed for a person to move.
2. The scientist would find that the amount of carbon dioxide exhaled increases with increased amount of activity because a person's breathing rate increases when they exercise which causes the person to exhale more carbon dioxide. Carbon dioxide is not involved in the chemical reaction that supplies the energy needed for a person to move.
3. The scientist would find that the amount of carbon dioxide exhaled decreases with increased amount of activity because carbon dioxide is used in a chemical reaction to make glucose that can then be used in a chemical reaction that supplies the energy needed for a person to move.
4. The scientist would find that the amount of carbon dioxide exhaled is the same for all of the activities because the amount of carbon dioxide exhaled stays the same regardless of the amount of activity. Carbon dioxide is not involved in the chemical reaction that supplies the energy needed for a person to move.