Base your answers to questions [tex]\$2[/tex] through [tex]\$4[/tex] on the information below and on your knowledge of biology:

Respiratory Rates

A student completed a lab activity that demonstrated the connection between pulse rate, heart rate, and flow of blood during exercise. She left her class wondering if there is a connection between breathing rate and exercise. With the help of her track coach, she conducted an investigation to try and find an answer to her question.

In the investigation, the respiratory rates of thirty athletes were measured before any exercise. To measure their rates, they counted the number of times they took a breath in one minute. Then, they ran one lap around the track, and their respiratory rates were determined again. Finally, they ran two laps around the track and checked their respiratory rates one last time. All of their data were recorded, and the averages were calculated. The data table shows the information obtained in this investigation.

The Effect of Exercise on the Respiratory Rates of Thirty Athletes

\begin{tabular}{|c|c|}
\hline Type of Activity & \begin{tabular}{c}
Average Respiratory Rates \\
(breaths per minute)
\end{tabular} \\
\hline At rest & 13 \\
\hline After one lap & 30 \\
\hline After two laps & 38 \\
\hline
\end{tabular}

Note: The answer to question [tex]\$2[/tex] should be recorded on your separate answer sheet.

[tex]\$2[/tex] During this activity, what was the purpose of finding the respiratory rates of the students at rest?
1. To determine if the students were healthy
2. To practice using the timer
3. To use as a comparison
4. To use as the variable