They're neither a confirmation nor an exception to cell theory. A confirmation of cell theory is new cells coming from pre-existing cells. read more
Viruses are an exception to the cell theory because they don't divide and multiply by themselves. They need living systems for their growth and multiplication. Because of this requirement of living system as medium to grow, viruses almost always cause diseases in hosts. read more
CELL THEORY: (SCHLEIDEN AND SCHWAAN) 1.All living things are made of cells. 2.A cell is the basic unit of life. (addition by virchow) 3.New cells arise from pre existing cell. Virus are an exception because viruses are alive only until they are inside their host cell .They are considered to behave dead when outside the host cell. read more
Viruses are considered an exception to the cell theory because they not classified as a living thing. All the do is have a cell make more of them. The cell theory states that all living things are made of cells. read more