Virus Characteristics

1. Viruses are acellular:
Viruses are considered acellular because they are not composed of cells. Instead, they are composed of genetic material (DNA or RNA) surrounded by a protein coat called a capsid. Some viruses may also have an outer envelope derived from the host cell's membrane. However, they lack the cellular machinery necessary for growth and metabolism, which is a defining characteristic of living organisms.

2. Viruses are smaller than bacteria:
Viruses are generally much smaller in size compared to bacteria. While bacteria are considered microscopic organisms that can be seen under a light microscope, viruses are even smaller and usually require an electron microscope to be visualized. The size of viruses typically ranges from about 20 to 300 nanometers, while bacteria can vary in size from about 1 to 10 micrometers.

3. Viruses cannot perform all metabolic activities outside a living host:
Unlike living organisms, viruses lack the necessary cellular machinery to carry out metabolic activities such as growth, reproduction, and energy production. They are obligate intracellular parasites, meaning they require a host cell to carry out their life cycle. Once inside a host cell, viruses hijack the cellular machinery to replicate their genetic material and produce new virus particles. Outside a living host, viruses exist in a dormant state and cannot carry out these metabolic activities.

4. Viruses are non-living organisms:
Viruses are often considered non-living because they do not exhibit the characteristics associated with living organisms. They lack cellular organization, independent metabolism, and the ability to reproduce on their own. Viruses are entirely dependent on host cells for their replication and survival. However, they do possess genetic material and can undergo evolution through mutation and natural selection.

Summary:
The incorrect statement among the given options is option 'C' - Viruses can perform all of their metabolic activities except reproduction when outside a living host. Viruses are acellular, smaller than bacteria, and cannot carry out metabolic activities outside a living host. They are considered non-living organisms due to their dependence on host cells for replication and lack of cellular machinery for growth and metabolism.