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


The presence of life process is the fundamental criteria for any organism that can be said to be alive or not.

  • Movement is the basic character for the organisms that are alive. Also they are some microscopic organisms that always move but cannot be seen with our naked eye. And also there are some organisms like plants and some other animals like sponges that cannot move but have life.

  • Growth is the major principle that says the organisms are living or non living. The plants and animals have growth in their life cycle. Some organisms also have regenerating capacity which means they can again grow their parts which are lost. Also some microscopic organisms which cannot show growth are also considered living organisms.

  • Respiration is the life process, for any organism to have life must have to respire. Unicellular organisms respire through diffusion, multicellular organisms through different processes and highly complex organisms have respiratory systems.

  • Reproduction is also another life process that almost all organisms have. Unicellular organisms have reproduction in the processes of binary fission, and in some other reproduction takes place as spore formation.

  • In plants reproduction takes place by budding, fragmentation ,and sometimes by vegetative propagation. 

  • In animals reproduction sexual where male and female gamets fuse together to form zygote and asexual reproduction where the male and female gamets doesnot fuse to form zygote.

Like this movement, growth, respiration, and reproduction are the major fundamental characteristics for any organism to say whether it is living or non lining, among them reproduction is the most prominent one.

Asexual reproduction by spore formation

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