In sunflowers, tall stems are dominant (S) over short stems. If the stem traits are determined by a single gene, what is the expected outcome of
crossing two sunflower plants that are heterozygous for tall stems? *
a. 50, tall stem: 50%. short stems
O b. 100% short stems
O . 100% tall stems
d. 75%. tall stems: 25% short stem

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.