1) As the body's chemical messengers, _____________________ transfer information and instructions from one set of cells to anoth
er. 2) A _______________ is a group of cells that produces and secretes, or gives off, chemicals.
3) Hormones are released into the bloodstream via small tubes called_________________.
4) Hormones find their way through the blood to their ___________________ cells.
5) Each hormone is a differently shaped key that will only fit into the correct __________________ lock.