Question

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

Answer 1

Hint: There are various processes that help in differentiating whether the given organism is alive or not. The criteria of living and non-living is based on various ways of identification.

Complete answer:
Living beings are known as organisms. These are similar to non-living objects in one thing; they are formed of the same elements which combine in a similar way to form similar molecules. But in living beings, the molecules are known as biomolecules.
Living organism show some basic properties which are given below:
-They have a cellular nature so they are either unicellular or multicellular.
-They have the ability to show locomotion and movement.
-They show various metabolic functions in the presence of energy.
-They show growth and development and grow in size.
-They have various regulatory mechanisms like nervous and hormonal systems in animals. -These maintain the homeostasis in the body.
-They show adaptations to their external environment to survive better. Individuals those better adapt to the surrounding replace those with less favourable characteristics.
-They have the power of reproduction and produce offspring and perpetuate themselves.
-There are different levels of organisation in living organisms like cellular level, tissue level, organ level and organ system level.

Note:
Father of zoology and Biology and father of Embryology: Aristotle
Homeostasis is the maintenance of a constant internal environment of the body of a living organism.
The regulation of the body heat in response to the internal and external environment of the body is called thermoregulation.
Growth is the most important characteristic of living organisms. It involves cellular differentiation, cellular proliferation and enlargement.