If,using visible movement as the defining characeterstic of life is not enough then how can we decide whether what is alive and what's not?
Difference between what is alive and what's not?
Living organisms carry out the life processes, which are vital to maintain the living state of an organism. These include nutrition, transportation, excretion, respiration, reproduction and control and coordination. If an organism carries out all these life maintaining activities, then the organism is alive.