Oral contraceptives often contain synthetic estrogens and progesterone for 21 days, and then placebo pills that do not have hormones for days 22-28. Why would this prevent pregnancy? Do such pills prevent ovulation? Do they prevent menstruation? Explain.

The famous scientist galileo galilei did several experiments with sloping planes, which he rolled metal balls down so that he could study motion. by changing the slope, he could study how the speed at which the ball rolled was affected. what was the dependent variable in galileo's experiment?

You are assessing an 86-year-old postoperative patient who has an unexpressive, stoic demeanor. when you enter the room, the patient is curled into the fetal position and your assessment reveals that his vital signs are elevated and he is diaphoretic. you ask the patient what his pain level is on a 0-to-10 scale that you explained to the patient prior to surgery. the patient indicates a pain level of “three or so.” you review your pain-management orders and find that all medications are ordered prn. how would you treat this patient's pain?

Which of the following statements about the societal costs of tobacco use is true? a. tobacco use affects the tax rate of only those individuals who smoke. b. the negative effects of tobacco use are only experienced by the smoker. c. tobacco users contribute to an overall loss of productivity. d. increased healthcare costs are mainly absorbed by tobacco users