Answer:
Virus
Explanation:
A virus is an infectious particle which is composed of the genetic material enclosed in a protein structure called capsomere.
Since the virus does not fulfil the criterion of a living thing like it has its metabolism, reproduction, growth, movement and cellular structures therefore it is considered as a non-living thing.
Since the virus does not have reproductive machinery therefore they use the DNA replication machinery of host. They use the host's machinery by integrating their genome in the genome of the host and replicate their genome. Through this mechanism, they make copies of them.
Thus, the virus is the correct answer.
