Answer:
Because they can only reproduce in a living cell
Explanation:
Virus is an organism that is incapable of replicating on its own without a living host. A virus infects a living host and makes use of Its replicational ability to produce new virions. A virus consists of a genetic material surrounded by a Protein called CAPSID. It does not possess the characteristics of other living organisms.
This means that it does not carry out any of the features a living cell undergoes e.g reproduction, respiration etc. Due to this reason, it is not classified as a living thing. They don't possess organnelles that carry out this peculiar functions.
A virus is considered a peculiar microorganism because it can only live and reproduce in a living host cell.
Answer:
They typically have a tough, spiny surface, which inspired their name (in Greek, echinos means “spiny” and derma means “skin”). They also have the unusual ability to regrow lost body parts, and sea stars and brittle stars can regrow arms if broken off or eaten
Explanation:
The smallest particle of any type of matter would be an Atom