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.

Latesha moore has a choice at work between a traditional health insurance plan that pays 80 percent of the cost of doctor visits after a $250 deductible and an hmo that charges an $8 co-payment per visit + a $20 monthly premium deduction from her paycheck. latesha anticipates seeing a doctor once a month for her high blood pressure. the cost of each office visit is $50. she normally sees the doctor an average of three times a year for other health concerns. comment on the difference in costs between the two health care plans and the advantages and disadvantages of each.