3. Which of the following is an example of how humans have selectively bred organisms for thousands of years? a. Humans have selectively bred lions to ensure they are adapted to the savanna.
b. Humans have selectively bred oak trees to produce acoms.
C. Humans have selectively bred apples to create lots of different varieties.
d. Humans have selectively bred cows so they produce less meat.

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.