The client puts a special trust in the massage therapist, who is then obligated to look out for the client's best interests. In legal terms this is called a(n):

In severe cases of snoring, patients may need surgery to trim excess tissues in the throat; this is called a(n) ________. 

Fill in the blank(s) with the appropriate word(s).

Which level of research evidence is the weakest?

a. An integrated review of experimental, quasi-experimental, and outcome studies b. A meta-analysis of correlational studies c. A single experimental study d. A single qualitative or descriptive study