An active virus, like all viruses has to "hijack" a host cell's DNA and then that DNA makes virus parts instead of cell parts. When the cell is full of the virus parts, it ruptures and dies. The viruses find other cells and repeat the cycle.
Multiply. A virus needs energy to multiply.
A basic characteristic of a virus is that it cannot survive or reproduce on its own. It requires a host cell to replicate and multiply.
No, a virus cannot catch a virus and become ill. A virus is a shell of protein containing DNA. A virus works by getting into a cell and "reprogramming it" to multiply and start to take of the organism. A virus cannot infect another virus because viruses are not cells themselves.
virus
multiply
To insert into a healthy cell so that it can multiply.
Viruses can only multiply (reproduce) within a host cell. The type of host cell is dependent on the virus' host range.
Your question does not give enough information. What are "which"? Should there be more to the question?
Reverse transcriptase. Runs off a DNA strand(s) from the virus RNA template.
Viruses replicate inside the host cells they infect. They hijack the cellular machinery of the host to make copies of themselves, leading to the multiplication of the virus.
zero.
A foodborne virus can only reproduce inside the body of a living host, such as a human or animal. Once ingested, the virus can multiply in the host's cells and cause illness.