Dr Kiecolt-Glaser Is a Health Psychologist Studying Whether Stress Impairs

Dr. Kiecolt-Glaser is a health psychologist studying whether stress impairs the body's ability to heal. In the highly stressfull week before final exams, dental students are given an oralpunch biopsy-a small sample of gum tissue is removed. The number of days for the oral wound to completely heal is recorded. The same dental students receive a second oral punchbiopsy during summer vacation. Once again, the number ofdays until the oral wound completely healed was recorded.What is the independent variable in this study?

A) number of days for the oral wound to heal
B) whether the oral wound was created during a high stress or low stress period
C) whether the dental students were working or relaxing during the summer vacation
D) average number of hours of sleep the students experienced in the day immediately following the gum wound