This table is simplified. It is missing a few taxa. What levels are missing and where do they belong in the table?
A. class, order, and family go between phylum and genus
B. class, family, and order go between kingdom and phylum
C. class goes after kingdom, order goes after phylum, and family goes after genus
D. order goes after kingdom, family and class go after phylum

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.