Question

Which of the following features can be said to be true defining features of living beings without any exception?
A) They can digest their food.
B) All of them can reproduce.
C) They can regenerate.
D) They can respond to external stimuli.

Answer 1

There is no proper definition of life but life is defined as organisms are open systems that balance equilibrium and goes through the various processes like metabolism, development, stimulation, adaption, reproduction and evolution and also include non-cellular life forms ex: viruses and viroids.

Complete answer:

Living systems are open self-organizing living things which interact with their environment and this living system is maintained by flows of information, energy, and matter.
All organisms in the living system which include simple prokaryotes to complex eukaryotes can feel and act to the environmental danger.
Plants also respond to several environmental factors like light and water.
Plants have the self consciousness property so that is why they can feel any changes in the environment.
This property which seems in all living beings.

Additional information:

Photoperiodism is occurring in both animals and plants, it is the physiological reaction that responds to the external stimuli.
Cells are the vital structure in every living being.
There are two types of cells: Prokaryotic (lack of nucleus) and eukaryotic cell (having the nucleus).

Hence, the correct answer is option ‘D’ i.e, they can respond to external stimuli.

Note: Homeostasis, organization, metabolism, growth, adaptation, response to stimuli and reproduction are the complex processes which play vital roles in balancing the life such as signaling and controlling the various mechanisms.