If for every action, there is an equal and opposite reaction, then how can forced be imbalanced? for example, somebody skydiving?

The force isn't 'imbalanced.' It's simply the result of the acceleration caused by the forces. You also need to take into account atmospheric pressure, air resistance and many other factors.

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.