Answer:
All exothermic reactions _c.release energy____
Explanation:
Exothermic reactions are those that give off energy, for example in the form of heat in combustion (it has a negative enthalpy variation, the energy of the products being less than the energy of the reagents)
The answer I'm pretty sure is a because it can't be d because ionic binding the electrons are affected and it can't be c because that's covalent bonding and it can't be b because they don't swap electrons.
The rate at which a radioactive isotope decays is measured in half-life. The term half-life is defined as the time it takes for one-half of the atoms of a radioactive material to disintegrate. Half-lives for various radioisotopes can range from a few microseconds to billions of years.