When a muscle is stretched by a contraction of the opposing muscles what is is called?

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

thermal energy is the answer

c. newton's third law of motion