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.
The make energy from sunlight through photosynthesis.
White blood cell is the answer
The central nervous system of the frog is different from that of humans; if the optic nerve of a frog is cut, the animal will be able to see again within weeks but the same damage in humans would cause permanent blindness :).
Puffapod (if this is for Harry Potter )
