Which statement describes the Potomac Shenandoah watershed? Check all that apply.
It flows into the James River
It includes part of West Virginia
It is the northernmost watershed
It is one of the largest watersheds.
It is a mixture of fresh and salt water.

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.