What criteria do we use to decide whether something is alive?

Q. What criteria do we use to decide whether something is alive?

 

Answer:-

Living organisms must keep repairing and maintaining their body structures. All these structures are made up of molecules. They must be capable of moving molecules around, all the time. So, molecular movement is one necessary criterion for something to be alive. However, molecular movements are generally not visible to the naked eye. Other such criteria including visible movements are like – walking, breathing etc.