15. Explain how the atomic mass of an element is affected by the distribution of its isotopes in nature.

Aform of energy that is reflected or emitted from objects in the form of electrical and magnetic waves that can travel through space. there are many forms of  electromagnetic  energy including gamma rays, x rays, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves.

Ithink the answer is fusion 

Two cars collide, lock bumpers and move together after the collision.this collision is known as perfectly inelastic collision.