An electromagnet is a nothing but a piece of iron with piece of wire wrapped around it creating an electrical charge when there is a closed circuit. This charge makes a nonmagnetic object magnetic.
Force is energy exerted. When using simple machines, you are trying to limit the force used by humans because exerting too much energy causes exhaustion.
Oxygen is a necessary element in the lives of almost to all organisms. One of the Earths most plentiful gasses, Oxygen goes through many natural and man made cycles each day.
S is for species. Species are not only a way to define different types of organisms, but also the lowest of the seven levels of classification; coming after Genus ,family, order, class, phylum, and kingdom.
U is for Ultraviolet Radiation. Ultraviolet radiation(UV rays) is electromagnetic radiation with a wavelength shorter than visible light. It is light energy created by an electromagnet.