Which action would most likely increase the greenhouse effect?
O
A. Use less electricity in your home
O
O
B. Use more coal to make electricity
c. Drive gasoline-powered cars less often
O
D. Plant new trees in the Amazon

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.