We can use the word RINGER to memorize the characteristic of living things.
Respiration - the ability to breathe and respire.
Irritability - the ability to detect and react to stimulus
Nutrition - taking in nutrients (eg. Food) for energy to growth, repair etc
Growth - the permanent increase in size and mass
Excretion - to get rid of toxic, waste or excess materials
Reproduction - to make more of that organism.
In addition, there is also movement, which is an action which causes a change in place or position.
Only the organisms with these characteristics are categorized as living things.