<prompt> When does the metanephros become functional?At week 3 of developmentAt week 4 of developmentAt week 10 -12 of developmentJust before bih  <response>: The metanephros begins to form at week 5 and stas to function in the fetus at about week 10-12 The pronephros is not functional in humans. The mesonephros leaves behind mesonephric duct gets degenerated. 