To break a chemical bond, energy must be
(1) absorbed
(2) destroyed
(3) produced
(4) released

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins

The identities of substances are the same before and after which type of change

11) burning your hand when accidentally touching a hot plate is an example of which heat transfer? a. conduction b. convection c. radiation d. none of these