Question

The organisms which display properties of both living and nonliving are
(A) Viruses
(B) Diatoms
(C) Lichens
(D) Bacteria

Answer 1

Hint:Viruses are considered as connecting links between living and non-living organisms. This is because they possess characteristic features of both living and nonliving organisms. They are also known as intracellular parasites, as they are activated only inside a host and outside the host, they are inactive and considered non-living.

Complete answer:
Viruses are sub-microscopic, obligate (strict) intracellular parasites. The word virus is derived from a Latin word ‘poison’. Viruses are connecting links between living and nonliving organisms. An organism is called a connecting link when it possesses characters of two different organisms.

The living characters observed in viruses are as follows,
>Presence of nucleic acid and protein,
>Capable of undergoing mutation,
>Ability to proliferate or multiply inside a host organism,
Ability to infect and cause diseases in living beings,
>Showing irritability, and
>Host-specific.

The non-living characters observed in viruses are as follows,
>Can be crystallised,
>Absence of metabolism,
>Inactive outside the host,
>Do not show functional autonomy, and
>Energy producing enzyme systems are absent.

Understanding the options one by one,
(A) Viruses – This is the correct answer as they display properties of both living and non-living matter.
Whereas, option (B), (C) and (D) are incorrect. Bacteria are prokaryotic, unicellular, self-autonomous organisms. Lichens are slow-growing plants which are categorised under Pteridophytes. They are used as indicators of pollution. Diatoms are microalgae that are majorly present in oceans and soil.

Therefore, the correct answer option (A).

Note:Viruses possess nucleic acid surrounded by protein coat. They are considered living only when they enter into a host cell and proliferate itself. Outside the host cell, they remain inactive and die eventually. Metabolism is the defining property of living organisms, but it is absent in viruses. And, hence viruses are called as connecting links between living and nonliving organisms.