Read the hypothesis below and answer the question that follows. Individuals who smoke will have a higher frequency of developing cancer later in life.
Which of the following would not be a potential extraneous variable for the stated hypothesis?

A. the occurrence of lung cancer in subjects

B. exposure to secondhand smoke

C. the amount of cigarettes smoked per day by subject

D. the number of years as a smoker

76 year-old has dermatochalasis on bilateral upper eyelids. a blepharoplasty will be performed on the eyelids. a lower incision line was marked at approximately 5 mm above the lid margin along the crease. then using a pinch test with forceps the amount of skin to be resected was determined and marked. an elliptical incision was performed on the left eyelid and the skin was excised. in a similar fashion the same procedure was performed on the right eye. the wounds were closed with sutures. the correct cpt® code(s) is/are? a. 15822, 15823-51b. 15823-50c. 15822-50d. 15820-lt, 15820-rt