Visible movements only cannot be the defining characteristic of life. Molecular movements which are

Question

Visible movements only cannot be the defining characteristic of life. Molecular movements which are invisible to the naked eye are necessary for life. Viruses are said to be living as they also show molecular movements but only when they are inside a living cell. Living organisms are organised structures. They must keep repairing and maintaining their structures. Maintenance of an organism is the collection of processes like nutrition, respiration, etc. In absence of any one of these, life would be difficult. To remain alive, chemical energy is needed by the living organism to perform vital process. It provides energy to (a) maintain life processes, (b) Produce molecules for  repair  of worm  out cells,  and (c) for the  growth  of the body\ The process which involves intake of $\mathrm{O}_{2}$ from outside and breaking down of nutrient molecules to produce energy is called\

Professor PC Thomas Classes · Answer

(c) : Respiration is an oxidative process in which food substances such as carbohydrates, proteins and fats are burnt within tissues to form carbon dioxide, water and consequent release of energy. The released energy temporarily remains stored as ATP.