a. It grows better at lower temperatures than at higher temperatures. b. It grows better at higher temperatures than at lower temperatures. c. It grows equally well at low and high temperatures. d. Temperature has no effect on seed growth. Please select the best answer from the choices provided

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.