What is life?

Life is a complex thing that can be really hard to define. There are may different definitions, none that absolutely everyone can agree on, so we tend to describe it according to the context to which we are applying the definition. One way to define life is through the acronym MRS GREN. Each letter stands for something an organism needs to be considered 'living'. These are Movement, Reproduction, Sensitivity, Growth, Respiration, Excretion and Nutrition. If you have something which you don't know whether to describe as living, a good way to check is by going through the list and considering each word for that particular organism.