The diagram illustrates photosynthesis. Which best describes what is happening in the area marked Y? Oxygen is released into the atmosphere through stomata. Carbon dioxide is released into the atmosphere through stomata. Oxygen is released into the atmosphere through xylem. Carbon dioxide is released into the atmosphere through xylem.

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.