How is a virus different from a bacterium? A. A virus causes illness, but a bacterium does not.
B. A bacterium is a living cell, but a virus is not.
C. A virus is a living cell, but a bacterium is not.
D. A bacterium causes illness, but a virus does not.

option B

Explanation:

On a biological level, the main difference is that bacteria are free-living cells that can live inside or outside a body, while viruses are a non-living collection of molecules that need a host to survive.

the median of the data is 4.5.