When doctors discuss prenatal development, they often calculate the due date from the first day of menstruation. In fact, the baby’s gestational age is calculated from the first day of menstruation....

When doctors discuss prenatal development, they often calculate the due date from the first day of menstruation. In fact, the baby’s gestational age is calculated from the first day of menstruation. At a maternity clinic, an obstetrician mentions that when a woman is 10 weeks pregnant, the baby is referred to as a fetus.



Which of the following is the correct calculation of the baby’s age from the moment of fertilization, assuming a 28-day ovarian cycle?