What do viruses need to carry on?
Viruses need a host cell to be able to multiply. Once they get attached to the cell membrane or cell wall of a living cell, they can take it over and "make" the living cell produce virus particles instead of cell parts. These particles can assemble into more viruses and then they break out of the cell (killing it) and begin the process again. They cannot make more viruses on their own.
Three exceptions to the cell theory are viruses, mitochondria, chloroplasts, and where did the first cell come from. Viruses carry on life processes but need to replication inside a host cell. The mitochondria and chloroplast have their own genetic material and can reproduce independently within a cell.
Viruses are not included in any of the kingdoms of organisms because they are generally not thought of as truly alive. Unlike living things, viruses do not have cells (they are much smaller) and are basically just DNA (or sometimes RNA) wrapped in protein. Thya slo do not carry out any metabolic processes (like eating) and although they reproduce, they cannot do so by themselves, and need to "hijack" a living cell from an organism.
Once viruses are in your body, they are attracted to cells because they see a cell as a pleasant host. Viruses are not technically living because, even though they carry out many of the processes that living things do, they cannot do this by themselves, which is why they need another host body. A virus will attach itself to one of your cells, and inject it's DNA into the cell, causing it to become a…
The closest answer is parasitic since certain viruses harm the host cell in order to replicate and survive (not all viruses do, though). Chemosynthetic and photosynthetic would imply that viruses themselves contain the necessary biological machinery to carry out cellular functions, which they don't.