Number the sequence of events that initiate lactation.
________Estrogen and progesterone levels decrease when the placenta is expelled and prolactin stimulates milk production.
________ In the last month of pregnancy, placental estrogen, progesterone, and placental lactogen stimulate the production of prolactin.
________ Estrogen and prolactin stimulate acini in the mammary gland to grow and lactiferous ducts to branch.
________ Oxytocin binds to myoepithelial cells in the mammary glands and causes them to contract and eject milk.