The diagram below shows the basic structure of a virus particle as it exists outside a living host cell.



Outside a host cell, a virus particle is metabolically inert: it has no cytoplasm, no organelles and no enzymes of its own with which to carry out most of the seven characteristic life processes. Once it has injected its nucleic acid into a suitable living host cell, however, it hijacks the host cell machinery to make many copies of itself. Which one of the seven characteristics of living organisms can a virus therefore be said to exhibit, but only while it is inside a host cell?