How does the Gulf Stream affect weather in the United States? A.
It brings cooler temperatures from the poles.

B.
It brings cooler temperatures from the tropics.

C.
The warm surface currents help create storms and fog.

D.
The cool surface currents produce cooler weather and fog.

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.