Which of the following activities would most likely be done by a physiologist?
a. studying how bones, ligaments, tendons, and muscles create movement
b. researching the density of human bones compared to gorilla bones
c. comparing the hearts of people suffering from different heart diseases
d. examining the different layers of heart tissue

In an experiment examining the effects tai chi on arthritis pain, callahan (2010) selected a large sample of individuals with doctor-diagnosed arthritis. half of the participants immediately began a tai chi course and the other half (the control group) waited 8 weeks before beginning. at the end of 8 weeks, the individuals who had experienced tai chi had less arthritis pain that those who had not participated in the course.