Archaea are different from bacteria in that archaea a. have structures that are more similar to bacterial structures. b. have molecules that are different from eukaryotic molecules. c. have structures and molecules that are more similar to eukaryotes than bacteria. d. developed before bacteria.

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.