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.

Why did the scientist use the amount of oxygen used to compare the different activities?

1. Because the amount of oxygen used is related to the amount of energy needed. Oxygen is used to convert food molecules into the energy needed for a person to move.
2. Because the amount of oxygen used is related to the amount of energy needed. Oxygen is a reactant in a chemical reaction that supplies the energy needed for a person to move.
3. Because the amount of oxygen used is related to the amount of energy needed. Oxygen is formed during a chemical reaction that supplies the energy need for a person to move.
4. Because the amount of oxygen used is a measure of how fit a person is. Oxygen is not involved in a reaction that supplies the energy needed for a person to move.