Question 4

Body temperature, breathing rate, and heart rate increase with exercise.

This hypothesis directly correlates with the physiological responses expected from strenuous exercise, indicating that body temperature, breathing rate, and heart rate are likely to increase during and after physical activity.

A) Body temperature, breathing rate, and heart rate depend on the health of the subject.

While health can influence physiological responses, this option does not specifically address the effects of exercise on these parameters. Therefore, it does not align accurately with the focus of the investigation, which is on the immediate responses to exercise rather than overall health status.

B) Many of the body's systems respond to exercise.

Although this statement is true, it is too broad and lacks specificity regarding which systems are being measured in this study. The investigation is specifically concerned with heart rate, body temperature, and breathing rate, making this hypothesis less suitable than option C.

C) Body temperature, breathing rate, and heart rate increase with exercise.

This hypothesis is the most suitable as it directly addresses the expected increases in physiological responses due to strenuous exercise. The study's design, which measures heart rates before and after exercise, supports this hypothesis effectively.

D) Subjects at rest have better health than subjects that exercise.

This statement is misleading and does not relate to the investigation's premise. The study focuses on the physiological responses to exercise, rather than making comparative health judgments about resting versus exercising subjects.

Conclusion

Option C is definitively the right choice, as it accurately captures the expected physiological changes resulting from exercise, which is the core focus of the investigation. The other options either lack specificity, introduce unrelated health comparisons, or do not align with the measures taken in the study.