The ability of sperm cells to move along the ductus deferens is due to ________.  

  How many secondary oocytes ultimately develop from each primary oocyte?  

  Normally menstruation occurs when ________.  

  The cells that produce testosterone in the testis are called ________.  

  Secretion of progesterone stimulates ________.  

  Where are spermatozoa stored until they are fully mature?  

  Relaxin is a hormone produced by the placenta and ovaries. The function of this hormone is to ________.  

  The corpus luteum prevents loss of the implanted embryo through menstruation by secreting ________.  

  Which of the choices below is NOT a function of the vagina?  

Who determines the birth date?